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The development of an underground asset management tool in BGS

January 2009

January 2009

Authors:

K. R. Royse

British Geological Survey

Andrew M Tye

British Geological Survey

K. Linley

British Geological Survey

NSRI Corrosion Risk Map.

…

: Cast Iron Pipe Research Association corrosion rating

…

Underground Asset Management Report Generator.

…

User defined area of interest

…

Figure A1: Formation of a corrosion cell. (Metal is corroded at the anode.)

…

Figures - uploaded by K. R. Royse

Content may be subject to copyright.

Content uploaded by K. R. Royse

Content may be subject to copyright.

The Development of an

Underground Asset Management

Tool in BGS.

Information Products Theme

Internal Report OR/09/023

BRITISH GEOLOGICAL SURVEY

INFORMATION PRODUCTS THEME

INTERNAL REPORT OR/09/023

The Development of an

Underground Asset Management

Tool in BGS.

K.R. Royse, A.M. Tye, K.A. Linley and H.J. Napier.

The National Grid and other

Ordnance Survey data are used

with the permission of the

Controller of Her Majesty’s

Stationery Office.

Licence No: 100017897/ 2009.

Keywords

Asset Managment, Corrosivity,

Derived Product, Underground.

Front cover

Tunnelling in progress.

Bibliographical reference

ROYSE, K.R., TYE, A.M.,

LINLEY, K.A., AND NAPIER, H.J..

2009. The Development of an

Underground Asset Management

Tool in BGS.. British Geological

Survey Internal Report,

IR/09/028. 63pp.

from the British Geological

Survey’s work is owned by the

Natural Environment Research

Council (NERC) and/or the

authority that commissioned the

work. You may not copy or adapt

this publication without first

obtaining permission. Contact the

BGS Intellectual Property Rights

Section, British Geological

Survey, Keyworth,

e-mail ipr@bgs.ac.uk. You may

quote extracts of a reasonable

length without prior permission,

provided a full acknowledgement

is given of the source of the

extract.

Maps and diagrams in this book

use topography based on

Ordnance Survey mapping.

Keyworth, Nottingham British Geological Survey 2009

The full range of our publications is available from BGS shops at

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BRITISH GEOLOGICAL SURVEY

Acknowledgements

This report was produced as part of a project funded by Information Products and a NERC

Innovation grant. A large number of individuals in BGS have contributed to this project.

This assistance has been received at all stages of the study. Many individuals have freely

given there advice and knowledge to the project.

Contents

Acknowledgements...............................................................................i

Contents .............................................................................................. ii

Structure of report .........................................................................iv

1 Introduction..................................................................................1

2 Customer Need.............................................................................2

3 Current Asset Management tools and their limitations. ..........3

3.1 Current Asset management tools..........................................3

3.2 limitations with current asset management tools..................5

4 Data required and availability....................................................6

4.1 Physical Data ........................................................................6

4.2 Chemical data .......................................................................6

5 Demonstration Version of an Underground Asset

Management System..................................................................13

6 Conclusions.................................................................................16

key findings..................................................................................16

References..........................................................................................17

Appendix 1 Corrosion Processes in Soils ..................................18

Composition or galvanic cell corrosion. ......................................18

Concentration cell corrosion ........................................................19

Microbial corrosion......................................................................19

Stray Current Corrosion ...............................................................19

Appendix 2 Asset List and Descriptions for Humber Trent

Study Area ...............................................................21

Appendix 3 Sample Report ........................................................26

Collapsible ...................................................................................27

Compressible................................................................................27

Dissolution ...................................................................................29

Fractures.......................................................................................30

Running Sand...............................................................................30

Shrink Swell.................................................................................32

Slope Instability ...........................................................................33

iii

Areas of Coal Mining...................................................................35

Drift Thickness.............................................................................36

pH.................................................................................................37

Permeability .................................................................................38

Artificial Ground Permeability ....................................................40

Resistivity/Conductivity...............................................................41

Sulphate........................................................................................43

Sulphide .......................................................................................44

Water Saturated deposits..............................................................46

Antimony .....................................................................................47

Arsenic .........................................................................................49

Cadmium......................................................................................51

Chromium ....................................................................................53

Lead..............................................................................................55

FIGURES

Figure 1: NSRI Corrosion Risk Map ………………..………………3

Figure 2: Example plot of volumetric water content v thermal

conductivity (Wm-1 K-1) (from Hendrickx et al 2002) ……8

Figure 3: Summary Map of Sounding distributions (from Baker et

al 1996) …………………………………………………….9

Figure 4: Underground Asset Management report Generator…….….13

Figure 5: User defined area of interest ……………………………....13

Figure 6: Example of report output……………………………….....14

Figure A1: Formation of a corrosion cell…………………………..….17

TABLES

Table 1: Daily Leakage figures (Thames Water)………………….....1

Table 2: Cast Iron Pipe Research Association corrosion rating……...4

Table 3: Limit in characteristics for soil reinforcements……………..4

Table 4: General guide to corrosivity (from Cunat 2001)……………10

Table 5: Resistivity of soils based on their physical properties and

chemical composition (from Cunat 2001)…………………..10

Summary

This report describes the work carried out to scope the potential for BGS to develop an

Underground Asset Management tool. This work was funded through both a NERC

innovation grant and Science budget funding from the Information Products Theme.

The objective of asset management is ‘to ensure that assets deliver the required function

and level of performance in terms of service, in a sustainable manner, at optimum whole

life cost without compromising health, safety, environmental performance or the

organisation’s reputation’. It is in this context that this report discusses the data available

within BGS that could be provided to external organisations and how to communicate this

information to potential clients.

STRUCTURE OF REPORT

The introduction explains the background to the project and looks into why an asset

management tool may be required. The second chapter discusses customer need and likely

uptake if such a tool were developed. This leads into the third chapter where current tools

already on the market in the UK and their limitations are discussed. In the forth and fifth

chapters an outline is given of the availability of data critical to the creation of an asset

management system and how this could be developed into a tool. Finally we describe a

pilot system developed for the Humber–Trent region. The final chapter attempts to

summarise the key findings.

THAMES WATER LEAKAGE

MEGALITRES per DAY

2000-01: 688

2001-02: 865

2002-03: 943

2003-04: 946

2004-05: 915

2005-06: 894

Source: Ofwat

Table 1: Daily leakage figures.

1 Introduction

Thirty seven years ago the ‘Hoar Report’ was commissioned to evaluate the cost of

corrosion to the national economy of the UK. The report

estimated the cost to be approximately 3-4% gross domestic

product (GDP). Since then the development of new

construction materials and methods has reduced this cost to

an estimated 2.5% - 3.5% GDP (DTI, 2000). Whilst

corrosion is being managed more effectively, it is still a

significant concern and cost burden to the nation. In recent

years, public and media interest has focussed on the cost of

leakage from water supply pipelines, but buried assets,

whether pipe-work, cabling, sewers or building foundations,

present their own challenges as problems are largely hidden

from view and are difficult to assess and manage.

The susceptibility of pipelines to corrosion and degradation can be determined through the

analysis of a number of environmental factors, combined with knowledge of the age and

composition of the pipeline in question. It is clear that in order to improve underground

asset management in the UK there is a requirement for spatial knowledge of the corrosive

properties of the soil in which pipe-work and other underground infrastructure sit. The

production of GIS data layers showing the spatial distribution of corrosive properties,

either as individual properties or on a cumulative points system would aid users such as

utility companies and local authorities to make improved decisions regarding the routeing

of pipe-work, selecting anti-corrosion measures or materials and to manage maintenance

and renewal schedules. The challenge for BGS is to combine national-scope, local-scale

geological information into a GIS and then create a simple, easy to understand Asset

Management tool for the UK market.

This report provides summary of the requirements for underground asset management in

the UK today and looks at how BGS could provide and develop relevant spatial geo-

environmental datasets to aid and improve buried asset management within the UK.

2 Customer Need

Civil engineers and surveyors will always need to build structures and lay pipelines in

corrosive environments and it is therefore essential to address the problems that result

(Broomfield, 2006). Corrosion prevention is often the most economical solution when

compared with conventional removal and repair methods.

Interest in an underground asset management system has been shown by Thames Water in

relation to their current issues with pipeline leakage. Thames Water is currently

responsible for around 16,000 kilometres of water pipes under London of which 30% have

been there for more than 150 years, and 50% for more than a century. These ancient pipes

are made of cast iron and are now brittle and corroded from sitting in highly plastic clay

soil. Extra stresses have come from traffic and inflexible lead joints, which lock and

fracture producing leakage of water (Thames Water official website, 2008).

Leakage issues are increasingly important as water resources within Thames Water are

under increasing pressure from the climate change and population growth. Thames Water

currently identify areas in which burst pipes are likely by using historical and current

weather data. Leakage is often found to occur under cold conditions and when clay soils

expand and contract. This data could be refined if they knew where the most corrosive

soils and highly plastic clays are located.

In addition the network was developed by a whole host of small water companies and

repairs over the years have not been carried out systematically and have in certain

circumstances added to the profusion of pipes, many of which are not in use.

Recently, there has been an increasing awareness of the need to manage physical assets

more systematically. In May 2004, the Institute of Asset Management produced a

specification for Asset Management. This was updated in December 2008 along with

development of a toolkit for evaluating compliance to the specification. PAS (Publicly

Available Specification) 55 is specifically intended to cover the management of physical

infrastructure assets and in particular the assets that form the main element of those in the

built environment such as utility networks. PAS 55 gives guidance and best practice in

asset management, typically this is relevant to infrastructure, gas, electric and water

utilities. The standard is split into two parts: part 1 – specification for the optimised

management of physical infrastructure assets and part 2 guidelines for the application of

PAS 55 part 1. While PAS 55 is not required for non regulated industries it has been

generating more interest. In April 2008 OFGEM (the Office of the Gas and Electricity

Markets) reported that all gas and electrical suppliers had achieved PAS 55 certification.

This provides BGS with a ready market that requires detailed underground asset

management information in order to comply with the recommendations in PAS 55.

3 Current Asset Management tools and their

limitations.

3.1 CURRENT ASSET MANAGEMENT TOOLS

3.1.1 Soil Corrosivity Map.

Within the U.K., the main source of

information regarding soil corrosivity is the

National Soil Research Institute (NSRI) at

Cranfield University (Figure 3). Their

corrosion map is based on the methodologies

developed by Corcoran et al. (1977), Argent

& Furness, (1979) and Jarvis & Hedges

(1994). Their approach was to use a

combination of archive and new data with

respect to their soil series (domain) maps to

produce a corrosivity factor. This method

was based on the scheme originally devised

by the Cast Iron Pipe Research Association

(CIPRA) (1964), using a mixture of field

measurements and measured archive values

to produce an accumulative score for

potential corrosivity of ferrous pipes for each

soil series (map domain).

The NSRI map was created by:

1. Field measurements of resistivity and redox potential at depths of 0.79 and 1.59

meters for each soil series

2. Simultaneous collection of samples for laboratory measurement of minimum

resistivity, pH and soluble sulphate content.

This work has been included the CatchIS software as an ‘environmental risk modelling

tool’. CatchIS contains a suite of additional modules which supports the operational

management of underground assets for example water pipes called ‘LEACS’. This tool

predicts the risk of corrosion to piping by looking at the following factors:

1. Soil moisture: soil moisture levels exceeding 20 % are particularly susceptible.

2. Soil acidity: values less than pH 4 are likely to result in greater corrosion.

3. Soil aeration: poorly aerated soils. Soil aeration is generally measured by its redox

potential with values less the 400-430mV indicating a suitable environment for

sulphate reducing bacteria.

4. Electrical resistivity: soils with low resistivity will encourage corrosion. Values

less than 2000 ohm cm are likely to be aggressive

Figure 1: NSRI Corrosion Risk Map.

Once measured values are determined for these parameters a score can be calculated based

on the CIPRA rating system (Table 2).

Table 2: Cast Iron Pipe Research Association corrosion rating

Soil Property Range Points1

Resistivity <700 10

(ohm cm) 700 – 1000 8

1000 – 1200 5

1200 – 1500 2

1500 – 2000 1

>2000 0

pH 0-2 5

2-4 3

4-6.5 0

6.5-7.5 02

7.5-8.5 0

>8.5 3

Redox potential >100 mV 0

50-100 mV 3.5

0-50 mV 4

Negative(-) 5

Sulphides / sulphates + 3.5

Trace 2

Negative 0

Moisture Poor drainage, continuously wet 2

Fair drainage, generally moist 1

Good drainage, generally dry 0

3.1.2 American Association of State Highways and Transport Soil reinforcement

limits

Similarly, work has been carried out to devise safe limits (below which corrosion is less

likely to occur) such as those carried out by the American Association of State Highway

and Transportation Officials (AASHTO) which recommends the limits outlined in Table

3. These results are based on laboratory tests for corrosion/degradation of soil

reinforcements for mechanically stabilized earth walls and reinforced soil slopes.

Table 3: Limits in characteristics for soil reinforcements.

Property Standard Test Procedures

Resistivity ohm-cm >3000 AASHTO T-288-91

pH >5 < 10 AASHTO T-289-91

Organic content 1% max AASHTO T-267-86

Chlorides < 100 ppm AASHTO T-291-91

Sulphates < 200 ppm AASHTO T-290-91

1 A total of 10 points indicates that the soil

is certain to be corrosive to ferrous pipe

2 If sulphides or sulphates present and low

or negative redox results are obtained, 3

oints should be

iven for this ran

3.1.3 Department of Transportation, California formula.

A further study by the Department of Transportation in California used pH and laboratory

measurements of minimum resistivity (R) to estimate the service life of steel culverts as in

the equation below for soils with pH < 7.3.

Years = 13.79[Log10R-Log10 (2160-2490 Log10 pH] (eq.1)

3.2 LIMITATIONS WITH CURRENT ASSET MANAGEMENT TOOLS

The most significant limitation with current Underground Asset Management tools is the

limited number of factors used to determine an assets susceptibility to corrosion. In reality

a whole host of physical and chemical factors contribute to underground corrosion e,g, the

shrink-swell potential of the soil, fracture potential of the ground, meteorological

information and groundwater level as well as those factors already mentioned above.

Another significant issue is the complexity of the processes involved in creating corrosive

environments. These are described in detail in Appendix 1. Problems with estimating soil

corrosivity are a result of its potential to occur in very localised areas. For example, where

an obvious factor such as high sulphide content is not present in a soil, corrosion may still

occur, linked to other variables that are difficult to map. These may include local water-

logging or a difference in substrate composition created as the structure was placed in the

ground which then contributes to the formation of a corrosion cell. To improve on existing

tools, BGS would need to provide a tool which takes into account as many, if not all the

contributory factors and provide superior quality data.

It would be difficult to produce maps that show specific areas of likely corrosion with

geologies or along pipes as will occur and are described in Appendix 1. It is felt that the

domain approach used by NSRI to produce their corrosivity map is a reasonable and

logical approach. However it is a very broad brush approach to a very complicated and

variable problem and consequently doesn’t represent the true ground conditions

adequately. It is felt that with the development of GIS, Prop-Base and the Geotechnical

Database BGS would be able to produce a more statistically integrated approach than

NSRI which would result in a superior quality dataset. For example, the BGS

Geotechnical GIS demonstrates an approach whereby all available data for a domain is

presented using graphs linked to the spatial reference data and held in a GIS. Additionally,

statistical packages such as ‘R’ could be used to interrogate the Geotechnical Database and

provide up to date statistics for domains or areas within domains as new information is

added. This would improve the quality of information provided in the underground asset

management system as time goes on.

4 Data required and availability

Data required for an asset management system can be split into three headings: Natural

physical, Chemical and Contaminants effecting pipeline composition. A table listing and

describing all the assets used in the Humber-Trent pilot study area are given in Appendix

4.1 PHYSICAL DATA

Physical properties such as fracturing and shrink swell contribute to corrosion potential by

significantly weakening the pipeline material by causing them to bend and crack. The

physical data used for the pilot study was taken directly from the Geosure-50 data, (slope

instability, collapsible, compressible, dissolution, running sand, shrink swell) with the

addition of a fracture layer i.e. those deposits that are likely to contain a high proportion of

discontinuities. The fracture layer was derived for the project from the soil parent material

map and proximity to known faults. All these data sets are currently available and were

included in the demonstration version of the underground asset management tool.

4.2 CHEMICAL DATA

Several datasets already exist within BGS, that could contribute to assessing chemical

elements of soil corrosivity. These include datasets of coal mining areas, superficial

thickness, water saturated deposits, and permeability including that of artificial ground.

This information could be easily integrated into the Underground Asset Management

system. A number of useful but unavailable data sets were identified that require work to

generate applicable and valuable data relating to resistivity. In addition, the feasibility of

developing new datasets from existing data sources (Prop-Base and the Geochemistry

database) are considered.

4.2.1 Chloride (Cl-)

The stream data collected by the G-BASE project and collated in the Geochemistry

database could be used as a basis for development of the chemical data layers. For

example G-BASE stream water data could be assessed for its usefulness for the following

reasons

1. G-BASE stream water data has been taken from 1st or 2nd order streams. These

streams normally have small catchments with limited parent material complexity.

2. A considerable proportion of the base flow will be influent flow

3. Chloride is a conservative ion in soil and will not sorb to soil surfaces.

An initial requirement would be to use ArcGIS to delineate 1st and 2nd order stream

catchments on single parent materials and collate stream water data for these parent

materials. Once collated, the data could be statistically analysed (mean, median, and, box

& whisker plots). A further approach could be to analyse the major cation and anion

concentrations using Piper Diagrams to try and determine which waters have a high Cl-

ratio in their anion component. Both approaches may indicate those domains where Cl-

may be a contributing factor to corrosivity. Once the data has been analysed verification

with parent material properties would need to be undertaken.

A similar exercise could be carried out using Prop-Base in the future, when sufficient data

has been collected from consultants reports. This would provide a more stochastic and

reliable dataset.

In addition, some parent material types, particularly those that make up coastal soils,

where atmospheric sea salt deposition is a component would need to be investigated as

being possibly high in Cl-.

4.2.2 Sulphate (SO42-)

Sulphate could be examined using a similar analysis of G-BASE data to that of Chloride

above in the short term. However, sulphate is reactive and may undergo precipitation,

sorption and dissolution reactions with the material of the stream bed, particularly with the

pH change caused by CO2 de-gassing as pore waters reach the stream, which will give

erroneous results if just using G-BASE data.

However, statistical analyses of Prop-Base soil pore water SO42- data would offer an

opportunity to develop a more robust sulphate layer in the future. In addition, the Parent

Material Map exists as a source of information about the presence of high sulphide

mineral concentrations.

4.2.3 Salts

Some parent material domains e.g. Mercia Mudstone are known to have potentially high

salt concentrations because of the environment in which they were deposited. Again G-

BASE data could be used, specifically conductivity measurements. This would provide a

proxy for salt concentrations, which would then be combined with geology. This could be

mapped on a domain basis.

4.2.4 Sulphide / Coal mining areas

Soils with high sulphide contents have the potential to create acidity if oxidation of the

sulphide takes place. Within the U.K. these soils would generally be associated with black

shales, Jurassic mudstones, siderites and the coal measures. In addition, many metals are

hosted in sulphide ores e.g. sphalerite, galena and chalcopyrite. These areas should be

located through:

1. The mineral assessment within the BGS Parent Material Map

2. Old land use maps of mining areas combined with geological knowledge.

4.2.5 Soil acidity

The G-BASE project has collected some soil pH values, but this dataset is far from

complete for the whole country. However, it is now a regular measurement. Where

information isn’t available an assessment can be made from parent materials. For example,

parent materials with high carbonate concentrations will generally have high (alkaline) pH

values. Soils with high sulphide concentrations, high organic matter (e.g. peat) will

generally have low (acid) pH values. In terms of land-use, ancient and coniferous forests

will tend to be below pH 5, land used for arable agriculture will usually have pH values

between 6 and 7. G-BASE data could be used to generate mean / median values for each

domain type.

4.2.6 Soil Thermal Conductivity

Soil thermal conductivity (STC) is a contributing factor to corrosion through the transfer

of heat from the pipes into the surrounding soil. Increasing the soil thermal conductivity

can result in an increase in corrosion in underground assets. The flow of heat is directly

proportional to the conductivity of the soil (Webb, 1956). Important soil factors include

texture and mineralogy, bulk density, moisture content and salt concentration (Abu-

Hamdeh et al. 2000). The effects of increasing heat transfer are that soils can become more

‘aggressive’ by:

1. changing the moisture dynamics along the pipeline

2. Increasing the movements of salts (especially Cl-) thus leading to the formation of

corrosion cells.

Abu-Hamdeh et al. (2000) suggests that the thermal conductivity of soils can be divided

into two broad groups. These are:

1. Properties inherent to the soil itself (texture, mineralogical composition)

2. Externally managed properties (water content & soil management)

Water content is a major factor and is difficult to manage overall, but the way a soil is

managed can have effects on thermal conductivity particularly the management of

compaction which affects bulk density and decreases porosity. Abu-Hamdeh et al. (2000)

carried out a series of experiments to examine the effect of various properties on soil

thermal conductivity.

The Results can be summarised as follows:

1. At given bulk densities increasing moisture content increases STC for sand and

clay loam soils

2. Increasing bulk density increased STC

3. A decrease in STC was found as salt concentrations increased between 0.01 and

0.1 (kg /kg)

4. STC decreased as a function of organic matter in a clay loam.

Interpretation of the results suggest that increasing bulk density increases STC through

improved point to point contact of minerals whereas increasing moisture increases STC

because of improved heat transfer through water films surrounding particles.

Sandy soils exhibited higher potential thermal conductivity values compared to clay soils

suggesting that the greater number of particles required for the same porosity in a clay soil

may increase thermal resistance between particles.

Increasing salt content has been found to decrease soil thermal conductivity (Abu-Hamdeh

et al. 2000) or has been found to have no apparent effect (Van Rooyen & Winterkorn,

1959). The movement of moisture away from pipes caused by evaporation, the pipe being

the heat source, could potentially increase the salinity of pore waters around the pipe

leading to increased conductivity and the creation of corrosion cells (see Appendix 1).

Thermal properties of soil are typically measured using the dual-probe heat pulse

technique. It consists of two parallel needles inserted into the soil at a known distance. A

heat pulse is applied to one probe and the temperature at the sensor probe is recorded as a

function of time. This measurement allows three linked soil properties to be determined

i.e. thermal conductivity, heat capacity and thermal diffusivity. Various authors have used

models to predict soil thermal conductivity. These models generally use variables

including bulk density, texture and a range of moisture contents to develop models for

specific soil types. One attempt has been made to predict soil thermal properties using

pedo-transfer functions. Hendrickx et al. (2003) and Bristow (2002) predicted soil thermal

conductivity (λ) from an empirical equation

()()

[

]

vv CDABA

θθλ

−−−+= exp

Where θv is the volumetric soil water content and A, B, C, D, and E are soil dependent co-

efficients related to soil properties as below.

)1(8.2

49.074.01

93.073.157.0 ss

φφ

−−

8.2=

5.0

6.2

C+=

7.003.0 s

Where Ø is the volume fraction of a particular component, subscripts ‘q’, ‘m’, and ‘s’

indicate quartz, minerals other than quartz and total solids, and mc is the clay mass

fraction.

To generate information with respect to soil thermal conductivity, new data of direct

measurement or data required for pedo-transfer will need to be generated. For example,

pedo-transfer functions could be used on East Midlands G-BASE data because particle

size data has been obtained. Plots could be produced of volumetric water content v thermal

conductivity by using the pedotransfer factor of Hendrickx et al. (2003). Results would be

graphs of soil thermal conductivity v moisture content (Fig. 2). This could be used as a

guide to developing an appropriate corrosion coding system for a map.

Figure 2: Example plot of volumetric water content v thermal conductivity (W m-1 K-

1) taken from Hendrickx et al. (2002).

4.2.7 Resistivity / Conductivity

Probably the most important measurement in soil corrosvity are resistivity measurements.

Currently, BGS has no national scale information with respect to resistivity or the

conductivity of soil parent material. A laboratory assessment for ‘Minimum Resistivity’

can be made. Various laboratory protocols are available such as AASHTO T288 (1991).

The procedure is relatively simple and involves packing a small box with the relevant soil

and inserting probes to measure the resistivity. The resistivity measurement is made as soil

moisture is increased until the minimum resistivity is found.

A general guide to linking corrosivity to Resistivity (Cunat, 2001) is given below (Table

4). Cunat (2001) also produced a table indicating the corrosivity of different soil types. In

the first instance, this could be used as a guide to allocating Parent Material domains with

a range of resistivity measurements (Table 5).

Table 4: General guide to corrosivity (after Cunat 2001).

Corrosivity Resistivity (ohm.cm)

Very corrosive < 1000

Aggressive 1000 – 5000

Mildly corrosive 5000 – 10000

Slightly corrosive 10 000 -20000

Progressively less corrosive > 20000

Not corrosive 30000 – 100000

Table 5: Resistivity of soils based on their physical properties and chemical

composition after Cunat (2001).

Type of Soil Physical Properties Chemical Resistivity

Composition (ohm*cm)

Sand Particle sizes:

Fine: 0.02 / 0.06mm

Medium: 0.06 / 0.2mm

Coarse: 0.2 / 0.6mm

Good drainage

SiO2 10 00 – 500 000

Gravel Particle sizes

Fine: 2/6mm

Medium: 6/20mm

Coarse: 20/60mm

Excellent drainage

SiO2 20 000 – 400 000

Loam Plastic mixture

High Moisture

SiO2, Al2O3

Dissolved species

H+, Cl-, SO4

2-, HCO3

3 000 – 20 000

Clay Very plastic mixture

High Moisture

SiO2, Al2O3

Dissolved species

H+, Cl-, SO4

2-, HCO3

500 – 2 000

Silt Coarse Clay

High Moisture

SiO2, Al2O3

Dissolved species

H+, Cl-, SO4

2-, HCO3

1 000 – 2 000

Resistivity information is also available from the ‘National Resistivity Sounding

Database’. This was setup by the University of Birmingham for BGS in 1990 and

continued until approximately 1996. The working system was installed at the BGS on a

VAX 8700 using the oracle relational database management system. It contains more than

8200 soundings drawn from work carried out by a number of universities, BGS and a

small number of consultants (Barker, 1996). Figure 3 illustrates the distribution of

soundings. From the resistivity sounding data it would be possible to select a

representative suite of soundings for each geological code/unit.

Figure 3: Summary map sounding distributions 10km2 grid units (Baker et al 1996)

An alternative data source would be the large number of resistivity soundings collected as

part of regional geophysical surveys under the Land Survey’s mapping programme. The

majority of this data is only available as hard copy reports and would require digitising

and adding to the database. It would however compliment and supplement the

information contained within the ‘National Resistivity Database,’ providing greater

geological code/unit coverage.

A combined approach using soil particle size, the national parent material map, and data

from the resistivity sounding database could be used to derive a national resistivity dataset

for the UK. This should ideally, over time be augmented with additional measured data as

it is collected e.g. data collected by low-level airborne geophysical survey such as in the

Tellus project in Northern Ireland.

4.2.8 Drainage

The BGS Parent Material Map will have permeability ratings for each domain. In addition,

the potential for identifying wetness caused by slope could be determined using the DEM

combined with an algorithm to establish the ‘Compound Topographic Index’ such as that

run on Tapes-G (Gallant and Wilson, 1996). This will allow a better indication of moisture

variability within a given landscape.

4.3 CONTAMINANTS

A range of contaminant data was collected from existing G-Base data including antimony,

arsenic, cadmium, chromium and lead.

5 Demonstration Version of an Underground Asset

Management System.

One of the major problems in assessing soil corrosivity is that it can occur locally due to a

small change in conditions e.g. difference in moisture content at top and bottom of slope,

differences in resistivity with depth. These varying factors suggest that knowledge

throughout the upper 10m is required (the potential depth to which assets can be placed).

This must be a major consideration when assessing the type and presentation of data for

any asset management system.

With knowledge of potential depth as an added factor, it is evident that a combined

parameter approach providing users with a single corrosivity potential map would not be

appropriate and could be very misleading. A system providing users with a list of

parameters that could contribute to increasing the corrosion potential for a particular

underground asset was identified as the preferred option and developed for the pilot tool.

This system would enable users to rank parameters as more or less important depending

on the particular type of asset being assessed.

The demonstration system is based on the Trent Humber area – 54NW02W, as it

represents a variable range of geological environments. The project data, application and

results can be found on W:\Teams\Dev_Prod\UndergroundAssetMang\Data\GIS. The GIS

structure and report writing code were adapted from work done on the ConSept project

(Ander et al 2003).

The demonstration version of the Asset Management tool seeks to:

1. Combine national and local scale geological information into one location.

2. Provide information down to 15 m below ground level

3. Output a report highlighting the presence of potential hazards and their effect on a

range of construction materials

In this way users will be able to use the information to assess the risks to assets, either as a

means of prioritising maintenance and liability, or of improving design for new

installations. Figures 4 to 6 illustrate how simple the Underground Asset Management tool

might be to use and the type of output created from it. (See Appendix 3 for a sample

report).

Figure 4: Underground Asset Management Report Generator.

The Report Generator allows the user to select the area, the parameters and properties of

interest (Chemical, Physical or Contaminants) and define a search radius. The user can

select an number parameters and properties in the selection list.

Figure 5: User defined area of interest

Figure 6: Example of report output (for further details see Appendix 3).

6 Conclusions

Evaluation of identified customer requirements for underground asset management

information, (in particular Thames Waters requirement to satisfy PAS 55

recommendations), the types of products already on the market, the type of data that is

needed and a demonstration tool have been presented in this report. This report has also

highlighted BGS’s ability to develop and produce an asset management tool to meet the

market need, and improve on those currently available.

KEY FINDINGS

1. Due to the continued need to build new assets in potentially corrosive environments

and to manage old assets particularly utility pipelines, to prolong their life or to tackle

repairs in a systematic way, there is an increasing need within industry for detailed

underground asset management information.

2. Current Underground Asset Management tools do not fulfil user requirements as

systems do not contain information on all known variables and the information they do

contain is of too lower resolution to meet most user needs.

3. The data requirements for an Underground Asset Management system would rely

heavily on the completion of G-base in order to obtain national coverage. If this

information isn’t readily available it would be essential to obtain geochemical

information for London and the South East of England in order to create complete and

consistent data coverage suitable for VAR uptake and Utility company uptake.

4. The two essential datasets that need to be derived are those for thermal conductivity

and resistivity. Using existing BGS data (some of which is still in paper form and

would require digitisation) and published methodologies this information could be

derived satisfactorily but would require significant investment of time and resources.

5. The more stochastic the dataset the better, as this will provide a higher resolution

dataset. therefore an underground asset management system should aim to continually

update parameters, using current data and integrating as and when new data where

possible.

6. Asset management data is best presented as a set of related, complimentary data layers

which could be interrogated and ranked depending on the end users specific

requirements.

7. Potential exists for the development of an Underground Asset Management system but

currently the focus needs to be on developing the missing but potentially valuable

datasets rather than the technology to deploy such a system.

References

British Geological Survey holds most of the references listed below, and copies may be obtained

via the library service subject to copyright legislation (contact libuser@bgs.ac.uk for details).

The library catalogue is available at: http://geolib.bgs.ac.uk.

AASHTO. 1991. Standard Method of Test for Determining Minimum Laboratory Soil Resistivity. Document T 288, American

Association of State Highway and Transportation Officials

ABUHAMDEH, N.H. & READER, R.C. 2000. Soil thermal conductivity: Effects of density, moisture, salt concentration and organic

matter. Soil Science Society American Journal, 64, 1285-1290.

ANDER, E.L., QUIGLEY, S., LAWLEY, R.S., MARCHANT, A.P., SMITH, B, BROWN, M.J., FIORINI, E. & HOOKER, P.J. 2003.

ConSEPT: An integrated GIS methodology for the prioritisation of potentially contaminated land (issue 1.0) England. IR/03/15C.

118pp

BARKER , R., INKEN BLUNK ' AND SMITH, I.1996 Geophysical considerations in the design of the UK National Resistivity

Sounding Database . FIRST BREAK VOL 14: 45- 53

BRISTOW, K.L. 2002. Thermal conductivity. In J.H.Dane and G.C.Topp (eds). Methods of soil conductivity. Part 4. Physical

Methods. Soil Science Society of America Book Series #5, Madison, Winconsin. Pp.1209-1226.

BROOMFIELD J P. 2006. Corrosion of Steel in Concrete Understanding, Investigation and Repair. Second edition

CAST IRON PIPE RESEARCH ASSOCIATION 1964. Soil Corrosion Test Report: Ductile Iron Pipe.

CORCORAN, P., JARVIS, M.G., MACKNEY, D. & STEVENS, K.W. 1977. Soil Corrosiveness in South Oxfordshire, Journal of Soil

Science, 28, 473-484.

CUNAT, P.J. 2001. Corrosion resistance of stainless steels in soils and in concrete. Paper presented at the Plenary Days of the

Committee on the study of Pipe Corrosion and Protection. Biareritz.

DAVIES, J.R. 2000. Corrosion: Understanding the basics. IHS: American Technical Publication.

GALLANT J.C. AND WILSON, J.P. 1996. Tapes-G: A grid-based terrain analysis program for the environmental sciences.

Computers & Geosciences, 22(7), 713-722.

HENDRICKX, J.M.H., VAN DAM, R.L., BORCHERS, B., CURTIS, J., LENSEN, H.A. & HARMON, R. 2003. Worldwide distribution of soil

dielectric and thermal properties. Detection and Remediation Technologies for mines and minelike Targets VIII. Proceedings of

the SPIE, Vol 5089.

JARVIS, M.G. & HEDGES, M.R. 1994. Use of soil maps to predict the incidence of corrosion and the need for iron mains renewal.

Journal of the Institute of water and Environmental Management, 68-75.

MCBRATNEY, A.B., MISASNY, B., CATTLE, S.R. & VERVOORT, R.W. 2002. From pedotransfer functions to soil inference systems.

Geoderma, 109, 41-73.

SMITH, W.H. 1968. Soil evaluation in relation to cast iron pipe. Journal of American Water Works Association, 60, 221-227.

U.S. DEPARTMENT OF TRANSPORTATION. 2000. Corrosion/Degradation of soil reinforcements for mechanically stabilized earth

walls and reinforced soil slopes. Publication No. FHWA-NHI-00-044

WEBB, J. 1956. Thermal conductivity of soil. Nature, 177, 989.

Appendix 1 Corrosion Processes in Soils

The corrosion of assets in soil is predominantly caused by the creation of corrosion cells. This is

an electrochemical process that takes place in all soils to varying degrees. There are 3 types of

natural corrosion cells:

1. composition or galvanic cells

2. concentration cells

3. stress cells.

In soils, composition and concentration corrosion cells are those most likely to occur. The

general principle of corrosion cells is that currents are created by the formation of an electric

potential between a cathode and anode. The current leaves the surface of a metal (i.e. a metal

pipe) at the anode from where it enters the soil and travels by ionic conductivity. It then re-enters

the metal at the cathode to complete the corrosion cell.

In general the part of a metal structure in the more conductive soil e.g. greater moisture content

or higher salinity forms the anode whereas the soil in the less conductive soil forms the cathode.

Corrosion is thus accelerated at the anode (Figure 1).

Figure A1: Formation of a corrosion cell. (Metal is corroded at the anode.)

COMPOSITION OR GALVANIC CELL CORROSION.

Composition or galvanic corrosion cells occur when two different metals are in contact with each

other within an electrolyte. One of the metals will corrode preferentially according to their

relative positions in the galvanic series (ie. a stainless steel pipe will corrode less quickly than a

copper pipe). The galvanic potential represents the electrical potential that develops between

different metals in a given electrolyte against a standard reference electrode. If the two metals

have different electrode potentials, the electrolyte provides passage for the migration of metal

ions from the anode to the cathode. Thus, the anode will corrode more quickly than it may

otherwise have as the corrosion of the cathode is retarded. The relative position of the two metals

Cathode

Ionic Current

Anode

Electric Current

Soil

in the galvanic series gives a good indication of which metal is more likely to corrode more

quickly.

Factors such as moisture content and aeration can influence the rate of the process. It is possible

for galvanic corrosion to occur on a single type of metal if the electrolyte varies in composition,

thus forming a concentration cell.

CONCENTRATION CELL CORROSION

Concentration cell corrosion is probably the most common form of corrosion in soils and results

from the formation of oxygen concentration cells. An good example is a pipeline that travels

through two different types of soils that have different oxygen aeration characteristics (e.g. sand

and clay). The sandy soil will be well aerated whilst the clay is impermeable. An oxygen

concentration cell is then formed with the metal pipe in the clay soil being the anode and the

metal in the sand the cathode. Concentration cells can also be formed in structures that cross the

water table, since the supply of oxygen is abundant above and restricted below. This allows

localized corrosion to take place below the water table where the metal constitutes the anode. In

general, anodic regions can be formed under conditions of low pH, high salt content, low

aeration and high moisture whereas cathodic regions exist in high pH, low moisture and good

aeration.

MICROBIAL CORROSION

Microbially induced corrosion is caused by chemoautotrophs. Both metallic and non-metallic

materials can be corroded. Micro-organisms in any aqueous environments (such as soil pore

waters) will attach themselves to the surfaces of assets, causing a biofilm to be produced. Within

this biofilm the organisms change local environmental variables including oxidising potential,

temperature, elemental concentrations and the velocity of water through them. Thus, these local

environments can vary considerably from the bulk soil conditions. Bacterial colonies and

deposits form concentration cells, causing and enhancing galvanic corrosion cells to be formed.

In reducing conditions atmospheres sulphate-reducing bacteria are common. These include the

genera Desulfoubrio, Desulfomonus and Desulfotomaculum. These produce H2S that can react

directly with iron, steel, stainless steel, copper, aluminium and zinc causing sulfide stress

cracking.. Sulphate-reducing bacteria require an electrode potential of at least -100 mV to thrive.

Under aerobic conditions, some bacteria such as Ferrobacillus ferrooxidans can cause corrosion.

These consume Fe2+ ions and convert them to Fe3+ hydroxides. The local deposition of Fe3+

hydroxides on metal surfaces can create local corrosion cells.

Sulphur oxidising bacteria can produce sulphuric acid causing biogenic sulfide corrosion, a

bacterially mediated process whereby hydrogen sulfide gas is formed and its subsequent

conversion to sulphuric acid attacks concrete and steel. The hydrogen sulfide gas is oxidized in

the presence of moisture forming sulphuric acid.

STRAY CURRENT CORROSION

Stray current corrosion occurs independently of environmental factors such as Eh (redox

potential) and pH (potential of H+) and results from electrical currents following unintended

pathways. The current leaves the intended path due to poor electrical connections or insulation

around the conductive material. It flows through the soil until it finds a buried metal structure in

the ground, such as a pipeline, that provides a lower resistance conducting pathway than the soil

for the earth return currents, causing increased corrosion.

Examples include direct current systems (electric railways, electric installations and cathodic

protection systems on pipe-works), interference currents from high voltage direct current power

lines with full or partial returns, long line currents in long unprotected pipelines laid in along

different soil types, electrical (magnetic) ground currents and stray currents from alternating

current systems. Moisture and conductivity of the soil will have an effect on current passage.

Appendix 2 Asset List and Descriptions for Humber Trent Study Area

HAZARDS

(Source) CLASS CLASS DESCRIPTION

A Class not used

B Class not used

C Deposits with the potential to collapse when saturated and loaded may

be present in places.

D Deposits with the potential to collapse when saturated and loaded are

probably present in places.

Collapsible

(No data for Humber

Trent)

E Class not used

A Compressible strata are not thought to occur.

B Compressibility and uneven settlement problems are not likely to be

significant on the site for most land uses.

C Compressibility and uneven settlement potential may be present. Land

use should consider specifically the compressibility and variability of

the site.

D Compressibility and uneven settlement hazards are probably present.

Land use should consider specifically the compressibility and variability

of the site.

Compressible

E Highly compressible strata present. Significant constraint on land use

depending on thickness.

A Soluble rocks are present, but unlikely to cause problems except under

exceptional conditions.

PHYSICAL

Dissolution

B Significant soluble rocks, but few dissolution features and no

subsidence; unlikely to cause problems except with considerable

surface or subsurface water flow.

C Significant soluble rocks, where there are dissolution features, and no

or very little recorded subsidence, but a low possibility of it occurring

naturally or in adverse conditions such as high surface or subsurface

water flow.

D Very significant soluble rocks, where there are numerous dissolution

features and/or some recorded subsidence with a moderate possibility

of localised subsidence occurring naturally or in adverse conditions

such as high surface or subsurface water flow

E Very significant soluble rocks, where there are numerous dissolution

features and/or considerable recorded subsidence with high possibility

of localised subsidence occurring naturally or in adverse conditions

such as high surface or subsurface water flow

A Running sand conditions are not thought to occur whatever the position

of the water table. No identified constraints on lands use due to running

conditions

B Running sand conditions may occur if the water table rises. Constraints

may apply to land uses involving excavation or the addition or removal

of water

C Running sand conditions may be present. Constraints may apply to

land uses involving excavation or the addition or removal of water.

D Running sand conditions are probably present. Constraints may apply

to land uses involving excavation or the addition or removal of water.

Running sand

E Running sand conditions are almost certainly present. Constraints will

apply to land uses involving excavation or the addition or removal of

water.

A Ground conditions predominantly non-plastic.

B Ground conditions predominantly low plasticity.

C Ground conditions predominantly medium plasticity.

D Ground conditions predominantly high plasticity.

Shrink/Swell

E Class not used

A Slope instability problems are not thought to occur but consideration to

potential problems of adjacent areas impacting on the site should

always be considered.

B Slope instability problems are not likely to occur but consideration to

potential problems of adjacent areas impacting on the site should

always be considered.

C Slope instability problems may be present or anticipated. Site

investigation should consider specifically the slope stability of the site.

D Slope instability problems are probably present or have occurred in the

past. Land use should consider specifically the stability of the site.

Slope Instability

E Slope instability problems almost certainly present and may be active.

Significant constraint on land use.

Chloride No data

Salts No data

A Heat flow is likely to be between 140 to 100 milliwatts per square

metre. These values are above the national average

B Heat flow is likely to be between 70 to 100 milliwatts per square metre.

These values are slightly higher than the national average

C Heat flow is likely to be between 40 to 70 milliwatts per square metre.

These are within the range that is considered typical for much of the

UK.

Thermal conductivity

D Heat flow is likely to be lower than 40 milliwatts per square metre.

These values are below the national average for the UK.

Present

Not present

Sulphate (no data)

Variable

CHEMICAL

(taken from G-base data or soil parent

material data)

Sulphide Present Sulphides are probably present. If oxygen in the air or groundwater has

access to unweathered deposits containing sulphides oxidation to

sulphates can occur

Not present Sulphide bearing strata are not likely to occur in this area

Variable There is a possibility that sulphide may be present in these deposits

A pH probably less than 5.

B pH likely to be between 5 and 9. Within the range of sulphate reducing

bacteria

C pH probably greater than 8

Resistivity/Conductivit

No data

Present Areas of coal mining are likely to be present. There is a high possibility

that mine waste with high concentrations of sulphides, sulphates and

metals may be present.

Areas of Coal Mining

Not Present Area unlikely to have been effected by coal mining

Present Area of ground likely to be permanently water saturated. Moisture

content of these deposits are likely to be high

Variable Area of ground likely to be seasonally waterlogged

Groundwater

Not present Area of ground likely to be above the water table. Moisture contents of

these deposits are likely to be low

Low Deposits likely to have a low permeability. The redox state in these

deposits is likely to be low unless the ground has been disturbed due to

previous construction work

Medium Deposits likely to have a moderate permeability.

Permeability

High Deposits likely to have a high permeability. The redox state in these

deposits is likely to be high unless the ground has been disturbed due

to previous construction work and backfill was with lower permeability

deposits.

Superficial Cover

Present Drift deposits of thickness probably greater than 10 m are likely to be

present. The thickness of drift deposits is likely to offer some protection

against sulphate rich rocks if present below

Variable Drift deposits of thickness between 0 and 10 m are likely to be present.

The thickness of drift deposits could offer some protection against

sulphate rich rocks if present but this would depend on the type of

construction proposed.

Not Present Drift deposits unlikely to be present. Bedrock likely to be unprotected.

Present It is likely that in these area levels of Arsenic are above 10 mg/kg.

Further site investigation may be required

Variable Arsenic known to be present in the area at levels likely to be below 10

mg/kg

Arsenic

Not present Arsenic not thought to be present in the area

present It is likely that in this area levels of Cadmium are above 3 mg/kg.

Further site investigation may be required

Not present Cadmium not thought to be present in the area

Cadmium

variable Cadmium known to be present in the area at levels likely to be below 3

mg/kg

Present It is likely that in this area levels of Chromium are above 600 mg/kg.

Further site investigation may be required

Not present Chromium not thought to be present in the area

Chromium

variable Chromium known to be present in the area at levels likely to be below

600 mg/kg

Present It is likely that in this area levels of Lead are above 500 mg/kg. Further

site investigation may be required

Not present Lead not thought to be present in the area

Lead

variable Lead known to be present in the area at levels likely to be below 500

mg/kg

Present It is likely that in this area levels of Antimony are above 10 mg/kg.

Further site investigation may be required

Not present Antimony not thought to be present in the area

CONTAMINANTS EFFECTING PIPELINE

COMPOSITION

Antimony

variable Antimony known to be present in the area at levels likely to be below

10 mg/kg

* Not currently being evaluated due to lack of data

Appendix 3 Sample Report

Underground Asset Management

Report Name: Underground Asset Management Test

Report Number: 1

Location

Physical

COLLAPSIBLE

Description: Deposits that may suddenly collapse and flow when saturated and loaded.

Represents a direct physical hazard to asset during installation and subsequently as

asset structure deforms due to ground movement. Asset or neighbouring

facilities/machinery can cause this hazard.

Effect: Direct hazard to installations during and post construction. Physical damage to

asset and/or environs.

Example: Burst water main, nearby heavy plant.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Data Resolution: 1: 50 000

No Collapsible deposits recorded in the Humber Trent test project area.

COMPRESSIBLE

Description: Deposits that compress or settle unevenly (subside) under loading.

Represents a direct physical hazard to all assets during installation and subsequently as

asset structure deforms due to ground movement. The asset or a neighbouring facility

can cause this hazard.

Effect: Asset may become compromised structurally as surround material ‘settles’

under loading of asset or neighbouring facilities.

Example: New buildings located adjacent to asset.

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

D Compressibility and uneven settlement hazards are probably present.

Asset managers should consider specifically the compressibility and

variability of the site.

E Highly compressible strata present. Significant constraint on Asset

management

A Compressible strata are not present

Search Radius Results

Class Description

D Compressibility and uneven settlement hazards are probably present.

Asset managers should consider specifically the compressibility and

variability of the site.

E Highly compressible strata present. Significant constraint on Asset

management

A Compressible strata are not present

Data Resolution: 1: 50 000

DISSOLUTION

Description: Deposits that contain water-soluble minerals, liable to subsidence.

Represents a direct physical hazard to all assets as asset structure deforms due to

ground movement. Natural or artificially induced groundwater conditions in soluble rocks

can cause this hazard.

Effect:

Example: New groundwater abstractions from specific geological strata.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

No dissolution information at this location

Search Radius Results

No dissolution data in the search radius

Data Resolution: 1: 50 000

FRACTURES

Description: Deposits that is likely to contain a high proportion of discontinuities across

which there has been a separation.

Effect: Direct hazard to installations during and post construction. Physical damage to

asset

Example: Assets fracture and break up due to movement along faults

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Data Resolution:

Data not currently available.

RUNNING SAND

Description: Deposits that flow due to saturation. Represents a direct physical hazard

to all assets, mainly during installation but also subsequently as asset structure deforms

due to ground movement.

Effect: Assets deformed or cracked.

Example: new excavations located adjacent to asset causing flow, or burst water main

asset.

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

C Running sand conditions may be present. Constraints may apply

asset management involving excavation or the addition or removal of

water.

A Running sand conditions are not considered to be a threat to asset

B Running sand conditions may occur if the water table is high (see

groundwater). Constraints may apply to asset management involving

excavation or the addition or removal of water

Search Radius Results

Class Description

C Running sand conditions may be present. Constraints may apply

asset management involving excavation or the addition or removal of

water.

A Running sand conditions are not considered to be a threat to asset

B Running sand conditions may occur if the water table is high (see

groundwater). Constraints may apply to asset management involving

excavation or the addition or removal of water

Data Resolution: 1: 50 000

SHRINK SWELL

Description: Deposits that swell or shrink unevenly as they dry out or become

saturated. Represents a direct physical hazard to all assets as asset structure deforms

due to ground movement. Natural or artificially induced groundwater conditions can

cause this hazard.

Effect: Assets cracked.

Example: Extensive drought, leaking water main.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

B Ground conditions predominantly low

plasticity.

C Ground conditions predominantly medium

plasticity.

A Ground conditions predominantly non-

plastic.

Search Radius Results

Class Description

B Ground conditions predominantly low

plasticity.

C Ground conditions predominantly medium

plasticity.

A Ground conditions predominantly non-

plastic.

Data Resolution: 1: 50 000

SLOPE INSTABILITY

Description: Locations where ground may slump, slide, fall or flow as a result of

deposit strength, saturation and topographic slope. Represents a direct physical hazard

to all assets during installation and subsequently as asset structure deforms due to

ground movement. Natural ground and drainage conditions can cause this hazard,

although some slips can be induced by earth workings

Effect: Deformation of asset structure.

Example: Prolonged heavy rainfall, slope steepness.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

C Slope instability problems may be present or anticipated. Asset

managers should consider specifically the threat of slope stability to

the asset

B Slope instability problems are not likely to occur but consideration to

potential problems of adjacent areas impacting on the asset should

always be considered.

D Slope instability problems are probably present or have occurred in

the past. Asset manager should consider specifically the threat of

slope stability to the asset.

Search Radius Results

Class Description

C Slope instability problems may be present or anticipated. Asset

managers should consider specifically the threat of slope stability to

the asset

B Slope instability problems are not likely to occur but consideration to

potential problems of adjacent areas impacting on the asset should

always be considered.

D Slope instability problems are probably present or have occurred in

the past. Asset manager should consider specifically the threat of

slope stability to the asset.

Data Resolution: 1: 50 000

Chemical

AREAS OF COAL MINING

Description: Locations where colliery spoil (sulphide rich) material may be present or

where undermining may have occurred: Represents a direct chemical hazard to metallic

and concrete assets as chemical reactions between assets and host material cause

corrosion (see section on sulphides). Artificially induced ground conditions cause this

hazard.

Effect: Asset managers should consider that there is a possibility that mine waste with

high concentrations of sulphides, sulphates and toxic metals may be present and may

affect a range of asset types.

Example: Acid corrosion of metallic materials.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable

Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Category Coalfield Description

Coalfield South Yorkshire

Coalfield Coal -

Inconclusive

Search Radius Results

Category Coalfield Description

Coalfield South Yorkshire

Coalfield Coal -

Inconclusive

Data Resolution: 1: 50 000

DRIFT THICKNESS

Description: Where there is thick drift (glacial) cover over sulphate and sulphide

bearing strata it is likely that shallow foundations will not penetrate into sulphate rich

rocks. The weathered zone in most geological deposits is between 2- 8m.

Effect: Assets protected from sulphate/ sulphide rich deposits due to thickness of drift

cover.

Example: Thick till coverage in northern England.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Class Description

Present Drift deposits of thickness greater than 10 m over your area.

Thick drift deposits are likely to offer some protection against

sulphate rich strata if present below.

Variable Drift deposits thickness between 2 and 10m. The thickness of

drift deposits may offer protection against sulphate bearing

strata below but this will depend on the permeability of the

strata.

Not

Present Drift deposits less than 2m thick. Thickness of drift deposits

unlikely to offer protection against sulphate bearing strata

below

Data Resolution:

Description: Deposits where measured pH is acidic or alkali. Represents a direct

chemical hazard to metallic and concrete assets during installation and subsequently as

chemical reactions between assets and host material cause corrosion. Natural ground

conditions cause this hazard.

Effect: Corrosion of underground assets.

Example: Acid corrosion of metallic materials.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Data Resolution: 10m cells

PERMEABILITY

Description: When permeability is high it is likely that the redox state of the deposit is

also high and when the permeability is low the redox state is likely to also be low.

Effect: If the redox state is low and the area is high in sulphates, waterlogged and PH is

between 5.5. and 9, conditions may be suitable for sulphate reducing bacteria.

Example: Corrosion of underground infrastructure.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description Maximu

m Minimu

m Flow

Type

High Deposits likely to have a high

permeability. The redox state in

these deposits is likely to be high

High High Mixed

Class Description Maximu

m Minimu

m Flow

Type

unless the ground has been

disturbed due to previous

construction work and backfill was

with lower permeability deposits.

Low Deposits likely to have a low

permeability. The redox state in

these deposits is likely to be low

unless the ground has been

disturbed due to previous

construction work

Low Very

Low Mixed

Search Radius Results

Class Description Maximu

m Minimu

m Flow Type

High Deposits likely to have a high

permeability. The redox state in

these deposits is likely to be high

unless the ground has been

disturbed due to previous

construction work and backfill

was with lower permeability

deposits.

High High Mixed

Low Deposits likely to have a low

permeability. The redox state in

these deposits is likely to be low

unless the ground has been

disturbed due to previous

construction work

High Very

Low Intergranul

Data Resolution: 1:50 000

ARTIFICIAL GROUND PERMEABILITY

Description: When permeability is high it is likely that the redox state of the deposit is

also high and when the permeability is low the redox state is likely to also be low.

Effect: If the redox state is low and the area is high in sulphates, waterlogged and PH is

between 5.5 and 9, conditions may be suitable for sulphate reducing bacteria.

Example: Corrosion of underground infrastructure.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset Affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

No artificial ground permeability information at this location

Search Radius Results

No artificial ground permeability information at this location

Data Resolution: 1: 250 000

RESISTIVITY/CONDUCTIVITY

Description: Deposits where measured resistivity or conductivity are anomalous.

Represents a direct chemical hazard to metallic and concrete assets during installation

and subsequently as chemical reactions between assets and host material cause

corrosion. Natural ground conditions cause this hazard.

Effect: Increase potential of corrosion.

Example: Resistivity/conductivity are products of groundwater and deposit chemistry.

Acidic, water/deposits bearing metallic salts are corrosive (and conductive).

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Legend Thermal

Conductivity

D Heat flow is likely to be lower than 40 milliwatts

per square metre. These values are below the

national average for the UK.

2.9

Search Radius Results

Class Legend Thermal

Conductivity

D Heat flow is likely to be lower than 40 milliwatts

per square metre. These values are below the

national average for the UK.

2.9

Data Resolution: 1: 250 000

Resistivity data currently under construction.

SULPHATE

Description: Deposits bearing suphatic minerals (e.g. gypsum). Represents a direct

chemical hazard to metallic and concrete assets as chemical reactions between assets

and host material cause corrosion.

Effect: Can directly corrode concrete – acidity.

Example: Presence of gypsum causing weakened concrete.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Site Results

Class Description

Present

Variable

Not Present

Data Resolution: 1: 50 000

The map shows the site (red) and a search radius of 350 meters (blue).

SULPHIDE

Description: Deposits bearing metallic sulphide minerals (e.g. pyrite). Represents a

direct chemical hazard to metallic and concrete assets during installation and

subsequently as chemical reactions between assets and host material cause corrosion.

Effect: Sulphides can react with oxygen to form sulphates which have a corrosive effect

on concrete.

Example: Oxidation of pyrite in backfill material creates sulphuric acid charged

groundwater (corrosion) and also growth of sulphate (corrosion and ground

displacement).

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description Lex Description

Not

Present Sulphide bearing strata are not

likely to occur in this area. SHERWOOD SANDSTONE

GROUP

Search Radius Results

Class Description Lex Description

Not

Present Sulphide bearing strata are not

likely to occur in this area. SHERWOOD SANDSTONE

GROUP

Data Resolution: 1: 50 000

WATER SATURATED DEPOSITS

Description: : If the area is water logged there is likely to be the possibility of conditions

being favourable for sulphate reducing bacteria and also a higher likelihood that

transportation of sulphates and other chemicals to underground infrastructure.

Effect: Water saturated deposits providing appropriate conditions for sulphate reducing

bacteria.

Example: Corrosion of pipelines.

Recommendation: Detailed site investigations may be necessary if in an area where

hazard occurs at a level where there might be design implications.

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class

Not

Wet

Search Radius Results

Class

Not

Wet

Data Resolution:

Contaminants

ANTIMONY

Description: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of Antinomy.

Effect: Exposure to Antimony can cause irritation to the eyes, skin and lungs. If

significant quantities are breathed in lung and heart problems may occur. If swallowed

in large quantities (over 19ppm) vomiting will occur, joint and muscle pain, anaemia and

heart problems have also been report.

Example: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of Antimony.

Recommendation: Levels of Antimony exceeding 10 mg/kg alternative pipeline

materials maybe required

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Antimony Point Data

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

Variable Antimony known to be present in the area levels likely to be

below 10 mg/kg

Search Radius Results

Class Description

Variable Antimony known to be present in the area levels likely to be

below 10 mg/kg

Antimony 10m grid

The map shows the site (red) and a search radius of 350 meters (blue).

Class Description

Present Likely that in this area levels of Antimony are above 10 mg/kg.

Variable Antimony known to be present in the area, levels likely to be

below 10 mg/kg.

Not

Present Antimony not thought to be present in this area.

ARSENIC

Description: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of arsenic.

Effect: Exposure to large quantities of arsenic may have significant health

consequences such as: irritation to the skin, lungs, stomach, and intestines; fatigue

abnormal heart rhythm, bruising, impaired nerve function, cancer and even death.

Example: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of arsenic.

Recommendation: Levels of Arsenic exceeds 50mg/kg, protection measures may be

required

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Data Resolution: 10m grid

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description Sample

Type Estimated As

(ppm)

Present Levels of Arsenic exceeds 10

mg/kg alternative pipeline

materials may be required

Soil 10.2

Variable Arsenic known to be present

in this area Soil 9.1

Search Radius Results

Class Description Sample

Type Estimated As

(ppm)

Present Levels of Arsenic exceeds 10

mg/kg alternative pipeline

materials may be required

Soil 12.7

Variable Arsenic known to be present in

this area Soil 9.1

CADMIUM

Description: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of cadmium.

Effect: Exposure to Cadmium can cause lung damage, brittle bones, possible kidney

disease, stomach irritation and are likely to be carcinogens.

Example: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of cadmium.

Recommendation: Levels of Cadmium exceeds 3 mg/kg alternative pipeline materials

may be required

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Cadmium Point Data

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

Variable Cadmium known to be present in the area at levels likely to be

below 3 mg/kg

Not

present Cadmium not thought to be present in the area

Present Area levels of cadmium above 3 mg/kg. Further site investigation

may be required

Search Radius Results

Class Description

Variable Cadmium known to be present in the area at levels likely to be

below 3 mg/kg

Not

present Cadmium not thought to be present in the area

Cadmium 10m grid

The map shows the site (red) and a search radius of 350 meters (blue).

Class Description

Present Area levels of cadmium above 3 mg/kg. Further investigation

may be required.

Variable Cadmium known to be present in the area, levels likely to be

below 3 mg/kg.

Not

Present Cadmium not thought to be present in this area.

CHROMIUM

Description: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of Chromium.

Effect: Exposure to chromium can cause irritation to the nose. Long term exposure can

cause lung cancer. Swallowing large amounts may cause stomach upsets, ulcers,

convulsions, kidney and liver damage and even death.

Example: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of chromium.

Recommendation: Levels of Chromium exceeds 600 mg/kg alternative pipeline

materials may be required

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Data Resolution: 10m grid

Chromium Point Data

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

Variable Chromium known to be present in the area at levels likely to be

below 600 mg/kg.

Search Radius Results

Class Description

Variable Chromium known to be present in the area at levels likely to be

below 600 mg/kg.

Chromium 10m grid

The map shows the site (red) and a search radius of 350 meters (blue).

Class Description

Present Levels of Chromium in this area likely to be greater than 600

mg/kg. Further investigation may be required.

Variable Chromium known to be present in the area, levels likely to be

below 600 mg/kg.

Not

Present Chromium not thought to be present in this area.

LEAD

Description: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of Lead.

Effect: Exposure to lead can cause damage to the nervous system, kidney,

cardiovascular and circulation, reproduction, personality, stomach and intestine and

joints and muscles and cancer.

Example: For certain types of infrastructure the design and layout, material

specifications and safety require a knowledge of the levels of lead.

Recommendation: Levels of Lead exceeds 500 mg/kg alternative pipeline materials

may be required

Types of Asset affected:

Asset Type

Pipes Clay/Vitric, Copper, Plastic, Steel

Foundations Concrete, Steel, Timber

Cable Copper, Fibre Optic, Plastic

Data Resolution: 10m grid

Lead Point Data

The map shows the site (red) and a search radius of 350 meters (blue).

Site Results

Class Description

Variable Lead is known to be present in the area at levels likely to be

below 500 mg/kg.

Search Radius Results

Class Description

Variable Lead is known to be present in the area at levels likely to be

below 500 mg/kg.

Lead 10m grid

The map shows the site (red) and a search radius of 350 meters (blue).

Class Description

Present Levels of Lead in this area likely to be greater than 500 mg/kg.

Further investigation may be required.

Variable Lead known to be present in the area, levels likely to be below

500 mg/kg.

Not

Present Lead not thought to be present in this area.

Data Resolution: 10m grid

Additional Comments

This report is aimed at customers or clients carrying out preliminary assessments of their underground assets, who

require a brief indication of the geological, physical and chemical factors that might influence the management of assets

underground.

The report prepared by BGS geoscientists and is based on analysis of records and maps held in the National Geoscience Data

Centre (NGDC).

This report is supplied in accordance with the GeoReports Terms & Conditions available on the BGS website at

www.bgs.ac.uk/georeports.

IMPORTANT NOTES ABOUT THIS REPORT

• The data, information and related records supplied in this report by BGS can only be indicative and should not be taken as a

substitute for specialist interpretations, professional advice and/or detailed site investigations. You must seek professional

advice before making technical interpretations on the basis of the materials provided.

• Geological observations and interpretations are made according to the prevailing understanding of the subject at the time. The

quality of such observations and interpretations may be affected by the availability of new data, by subsequent advances in

knowledge, improved methods of interpretation, and better access to sampling locations.

• Raw data may have been transcribed from analogue to digital format, or may have been acquired by means of automated

measuring techniques. Although such processes are subjected to quality control to ensure reliability where possible, some raw

data may have been processed without human intervention and may in consequence contain undetected errors.

• Detail, which is clearly defined and accurately depicted on large-scale maps may be lost when small-scale maps are derived

from them.

• Although samples and records are maintained with all reasonable care, there may be some deterioration in the long term.

• The most appropriate techniques for copying original records are used, but there may be some loss of detail and dimensional

distortion when such records are copied.

• Data may be compiled from the disparate sources of information at BGS's disposal; including material donated to BGS by third

parties, and may not originally have been subject to any verification or other quality control process.

• Data, information and related records, which have been donated to BGS, have been produced for a specific purpose, and that

may affect the type and completeness of the data recorded and any interpretation. The nature and purpose of data collection,

and the age of the resultant material may render it unsuitable for certain applications/uses. You must verify the suitability of the

material for your intended usage.

• If a report or other output is produced for you on the basis of data you have provided to BGS, or your own data input into a

BGS system, please do not rely on it as a source of information about other areas or geological features, as the report may

omit important details.

• The topography shown on any map extracts is based on the latest OS mapping and is not necessarily the same as that used in

the original compilation of the BGS geological map, and to which the geological linework available at that time was fitted.

Copyright in materials derived from the British Geological Survey's work, is owned by the Natural Environment Research Council

(NERC) and/ or the authority that commissioned the work. You may not copy or adapt this publication, or provide it to a third party,

without first obtaining NERC’s permission, but if you are a consultant providing advice to your own client you may incorporate it

unaltered into your report without further permission, provided you give a full acknowledgement of the source. Please contact the

BGS Copyright Manager, British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG. Telephone: 0115

936 3100.

Report issued by: BGS

This product includes mapping data licensed from the Ordnance Survey® with the permission of the Controller of

Design Oriented Linear-Equivalent Approach for Evaluating the Effect of Tunneling on Pipelines

Article

Full-text available

Jul 2015

The process of tunneling is associated with ground movements which may lead to stressing of nearby existing buried infrastructure , and potentially poses a risk of damage. The need for an effective evaluation method of the potential risk increases with the ongoing expansion of underground space utilization. This paper presents a new approach for evaluating the interaction between an assumed input of greenfield tunneling displacements and an existing buried pipeline. The approach integrates new developments with previous research findings to establish a practical interaction analysis methodology that can be used in design. It involves the use of an elastic-continuum analysis to solve the soil-pipeline interaction together with an iterative calculation of the equivalent stiffness in order to consider soil nonlinearity. A set of simplified closed-form expressions, which can be used to evaluate maximum pipeline bending moments within the suggested framework, are presented in the paper. A comparison of the new method results against centrifuge test data and advanced discrete element-method simulations is presented in the paper. The obtained agreement provides validation of the new method over a wide range of tunneling-induced volume losses and pipeline parameters.

Responses of pipeline to side-by-side twin tunnelling at different depths: 3D centrifuge tests and numerical modelling

Article

Jun 2017
TUNN UNDERGR SP TECH

The tunnel-pipeline-soil interaction has gotten momentum recently, but most of the previous studies were focused on the responses of pipeline to single tunnelling and simplified the interaction as a plane strain problem. Up to date, there is still a lack of research on the responses of a pipeline to twin tunnelling at different depths. This study presents a series of three-dimensional centrifuge model tests which were performed to investigate the effects of side-by-side twin tunnelling at varying depths on an existing buried pipeline in dry sand. In the centrifuge model tests, both the volume loss and the weight loss were simulated in-flight using a novel technique. To gain better understanding of the tunnel-pipeline interaction, the centrifuge tests were back-analysed numerically based on an advanced hypoplastic model, which accounts for strain- and path-dependent soil stiffness at small strains. Based on the physical and numerical investigations, it was revealed that the distribution of pipeline maximum shear force is greatly affected by the second tunnelling. The shifted distance of the pipeline maximum shear force induced by the second tunnelling in the case of cover-to-diameter ratio (C/D) of 2 was 80% larger than that in the case of C/D of 4. The major influence zone on the pipeline induced by tunnelling is within 1.2D (tunnel diameter) ahead of and after the tunnel face. When the pipeline is located within the major influence zone due to tunnelling, there was a sharp increase in the relative pipeline-soil stiffness and the additional bending strain in the pipeline. The tests results were compared with the results from a dimensionless chart and an analytic solution in the literature. Although these two approaches can reasonably predict the bending strain in the pipeline due to the first tunnelling, they fail to accurately capture the incremental bending strain solely caused by the second tunnelling. This implies that one should be cautious in using the superposition principle to predict the bending strain in a pipeline subjected to twin tunnelling. Because the deviatoric strain of the soil around the pipeline was increased by the second tunnelling, leading to further degradation of the soil stiffness around the pipeline.

External and Internal Corrosion of Large-Diameter Cast Iron Mains

Article

Dec 2013

Deterioration in cast iron mains manifests itself in the form of corrosion. External corrosion is typically found to occur in pipes buried in corrosive soils while internal corrosion is dependent on water chemistry and flow characteristics. In the literature, corrosion of cast ron pipes (external and internal) is typically characterized by corrosion pit depth even though corroded area and corroded pit volume as well as pit location may enhance this characterization. Knowledge of these corrosion pit properties permits the assessment of its structural integrity. Typically, internal and external corrosion pits and corroded areas are observed to occur in many irregular shapes and sizes, which make their characterization a challenge. This paper describes extreme value statistical models that can be used to estimate external and internal corrosion pit depths in cast iron pipes using indirect properties or parameters. The goal of these corrosion models is to be able to predict corrosion pit depth based on available data with an acceptable degree of confidence. The external corrosion model is calibrated using external corrosion ata collected by ThamesWater Utilities Ltd (TWUL) and subsequently validated with data obtained from the inspection of four cast iron pipe lengths. The internal corrosion model was calibrated using internal corrosion data but sufficient appropriate data was not available for its validation.

Soil Thermal Conductivity Effects of Density, Moisture, Salt Concentration, and Organic Matter

Article

Jul 2000

The thermal conductivity of soil under a given set of conditions is most important as it relates to a soil's microclimate. The early growth and development of a crop may be determined to a large extent by microclimate. The effect of bulk density, moisture content, salt concentration, and organic matter on the thermal conductivity of some sieved and repacked Jordanian soils was investigated through laboratory studies. These laboratory experiments used the single probe method to determine thermal conductivity. The soils used were classified as sand, sandy loam, loam, and clay loam. The two salts used were NaCl and CaCl2, while addition of peat moss was used to increase the organic matter content. For the soils studied, thermal conductivity increased with increasing soil density and moisture content. Thermal conductivity ranged from 0.58 to 1.94 for sand, from 0.19 to 1.12 for sandy loam, from 0.29 to 0.76 for loam, and from 0.36 to 0.69 W/m K for clay loam at densities from 1.23 to 1.59 g cm(-3) and water contents from 1.4 to 21.2%. The results also show that an increase in the amount of added salts at given moisture content (volumetric solution contents theta ranged from 0.03-0.12 m(3) m(-3) for the sand and from 0.09-0.30 m(3) m(-3) for the clay loam) decreased thermal conductivity. Increasing the percentage of soil organic matter decreased thermal conductivity. Finally, it was found that the sand had higher values of thermal conductivity than the clay loam for the same salt type and concentrations.

Soil corrosiveness in South Oxfordshire

Article

Jul 2006
EUR J SOIL SCI

The potential corrosiveness of four soil series was studied in south Oxfordshire by measuring soil properties (resistivity, pH, sulphate content, moisture content and redox potential) thought to be closely connected with ferrous metal corrosion. Fifty random points were located in areas of the soil series map units. Paired measurements of resistivity were made at each sampling point. Analysis of variance over all groups (soil map units) showed that, for all properties except redox potential, between group variance exceeded within group variance. The amount of variance contributed from within the pairs of resistivity measurements was small suggesting little short range variation in this property. There was good association between the properties measured and the soil map units. The kinds of soil identified and the delineations on the soil map therefore represents a useful partitioning of the areas studied in terms of corrosion risk.

Use of Soil Maps to Predict the Incidence of Corrosion and the Need for Iron Mains Renewal

Article

Jul 2007
WATER ENVIRON J

The requirement for revised asset management plans from water-supply companies and the need to prioritize the renewal of buried water-supply pipework has stimulated an interest in the spatial distribution of corrosion risk and intensity. This paper reports how the relationships between soil corrosion and the spatial distribution of soil types, as displayed on soil maps, can be combined to predict the likely incidence of aggressive soils and thereby identify those water mains which are most likely to need early replacement. The concept is illustrated by a project supported by Portsmouth Water plc.

TAPES-G: A grid-based terrain analysis program for the environmental sciences

Article

Aug 1996
COMPUT GEOSCI-UK

TAPES-G is a grid-based terrain analysis program that computes slope, aspect, upslope contributing area, profile and plan curvature and several other topographic attributes for each cell of a square-grid digital elevation model (DEM). These topographic attributes can be used to represent key physical processes in a form simple enough to allow modeling at catchment and larger scales. The program creates initially a depressionless DEM if desired. Upslope contributing area can be calculated using either the classical D8 algorithm, the quasi-random Rho8 algorithm, the multiple flow direction FD8/FRho8 algorithm or Costa-Cabral and Burges's stream tube-based DEMON algorithm. Stream networks, sub-catchments and the spatial distribution of individual attributes can be plotted interactively or copied to the ARC/INFO geographic information system (GIS) for further processing.

Pedotransfer functions to soil inference systems

Article

Sep 2002
GEODERMA

Pedotransfer functions (PTFs) have become a ‘white-hot’ topic in the area of soil science and environmental research. Most current PTF research focuses only on the development of new functions for predicting soil physical and chemical properties for different geographical areas or soil types while there are also efforts to collate and use the available PTFs. This paper reviews the brief history of the use of pedotransfer functions and discusses types of PTFs that exist. Different approaches to developing PTFs are considered and we suggest some principles for developing and using PTFs.

An integrated GIS methodology for the prioritisation of potentially contaminated land (issue 1.0) England. IR/03/15C

Jan 1996
45-53

Barker Consept 118pp
R Inken Blunk 'and
I Smith

ConSEPT: An integrated GIS methodology for the prioritisation of potentially contaminated land (issue 1.0) England. IR/03/15C. 118pp BARKER, R., INKEN BLUNK ' AND SMITH, I.1996 Geophysical considerations in the design of the UK National Resistivity Sounding Database. FIRST BREAK VOL 14: 45-53

Worldwide distribution of soil dielectric and thermal properties. Detection and Remediation Technologies for mines and minelike Targets VIII

Jan 2003

J M H Van Dam
R L Borchers
J Lensen
H A Harmon

HENDRICKX, J.M.H., VAN DAM, R.L., BORCHERS, B., CURTIS, J., LENSEN, H.A. & HARMON, R. 2003. Worldwide distribution of soil dielectric and thermal properties. Detection and Remediation Technologies for mines and minelike Targets VIII. Proceedings of the SPIE, Vol 5089.

Corrosion/Degradation of soil reinforcements for mechanically stabilized earth walls and reinforced soil slopes. Publication No. FHWA-NHI-00-044

Jan 2000

U S Department
Transportation

U.S. DEPARTMENT OF TRANSPORTATION. 2000. Corrosion/Degradation of soil reinforcements for mechanically stabilized earth walls and reinforced soil slopes. Publication No. FHWA-NHI-00-044

Corrosion: Understanding the basics

Jan 2000

DAVIES, J.R. 2000. Corrosion: Understanding the basics. IHS: American Technical Publication.

Soil evaluation in relation to cast iron pipe

Jan 1968
221-227

SMITH, W.H. 1968. Soil evaluation in relation to cast iron pipe. Journal of American Water Works Association, 60, 221-227.

The development of an underground asset management tool in BGS

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