ENGINEERING GEOLOGICAL STUDY ON THE SLOPE FAILURE ALONG THE KIMANIS TO KENINGAU HIGHWAY, SABAH, MALAYSIA

Abstract

The geology along the Kimanis to Keningau Highway provides a favourable setting for engineering geological
instability. The area is underlain by the Crocker Formation (Late Eocene to Early Miocene age) to vary recent
Quaternary alluvial materials which are still being deposited. Crocker Formation consists mostly of interbedded
grey sandstones and grey mudstones or shales. The sandstones are texturally immature where angular to
subrounded quarts grains are cemented by clay minerals and occasionally by calcite. The Crocker Formation has
also undergone intense deformation. The tectonic complexities influenced the physical and mechanical properties
of the rocks, resulting in a high degree of weathering and instability. The weathered materials are unstable and may
experience sliding due to by high pore pressure and intensively geomorphological processes. In this study, a total of
28 selected critical slope failures were studied and classified into two main groups: rock slope and soil slope. Failures
in soil slopes (including embankments) are 18 (64 %) whereas 10 of all failures (36 %) of rock slope. Soil slope
failures normally involved large volumes of failed material as compared much rock slopes, where the failures are
mostly small. Of the 18 failures in soil slopes, 6 (33 %) are embankment failures making them 21 % of all types of
failures. Kinematics rock slope analyses indicates that the variable potential of circular, planar, wedges and toppling
failures modes as well as the combination of more than one mode of aforementioned failure. Rock and soil slopes
stability analysis indicates that the factor of safety value as unsafe (0.50 to 0.96). The main factors causing slope
failure occurrences in the study area are natural (geology, meteorology, topography and drainage system) and
human factors (lack of proper planning, human activities and community’s attitude). Development planning has to
consider the hazard and environmental management program. This engineering geological study should be
prioritized and take into consideration in the initial step in all infrastructures program and it may play a vital role
in landslide hazard and risk assessment to ensure the public safety.

Full text

Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.
ARTICLE DETAILS
Article History:
Received 26 June 2018
Accepted 2 July 2018
Available online 1 August 2018
ABSTRACT
The geology along the Kimanis to Keningau Highway provides a favourable setting for engineering geological
instability. The area is underlain by the Crocker Formation (Late Eocene to Early Miocene age) to vary recent
Quaternary alluvial materials which are still being deposited. Crocker Formation consists mostly of interbedded
grey sandstones and grey mudstones or shales. The sandstones are texturally immature where angular to
subrounded quarts grains are cemented by clay minerals and occasionally by calcite. The Crocker Formation has
also undergone intense deformation. The tectonic complexities influenced the physical and mechanical properties
of the rocks, resulting in a high degree of weathering and instability. The weathered materials are unstable and may
experience sliding due to by high pore pressure and intensively geomorphological processes. In this study, a total of
28 selected critical slope failures were studied and classified into two main groups: rock slope and soil slope. Failures
in soil slopes (including embankments) are 18 (64 %) whereas 10 of all failures (36 %) of rock slope. Soil slope
failures normally involved large volumes of failed material as compared much rock slopes, where the failures are
mostly small. Of the 18 failures in soil slopes, 6 (33 %) are embankment failures making them 21 % of all types of
failures. Kinematics rock slope analyses indicates that the variable potential of circular, planar, wedges and toppling
failures modes as well as the combination of more than one mode of aforementioned failure. Rock and soil slopes
stability analysis indicates that the factor of safety value as unsafe (0.50 to 0.96). The main factors causing slope
failure occurrences in the study area are natural (geology, meteorology, topography and drainage system) and
human factors (lack of proper planning, human activities and community’s attitude). Development planning has to
consider the hazard and environmental management program. This engineering geological study should be
prioritized and take into consideration in the initial step in all infrastructures program and it may play a vital role
in landslide hazard and risk assessment to ensure the public safety.
KEYWORDS
Geological instability, Quaternary, grey sandstones, grey mudstones or shales, Soil slope.
1. INTRODUCTION
Landslide is among the major geohazard occurrences in Sabah, Malaysia.
As with flooding, tsunami, siltation and coastal erosion, landslides
repeatedly occurred in the region with disastrous effect. Landslide is a
general term for a variety of earth processes by which large masses of rock
and earth materials spontaneously move downward, either slowly or
quickly by gravitation [1]. Such earth processes become natural hazard
when their direct interaction with the material environment is capable of
causing significant negative impact on a property and human’s well being.
With the growth of human population and the expansion of the scope of
human’s activities in Sabah, we find ourselves increasingly in conflict along
steeply area [2]. A landslide zoning provides information on the
susceptibility of the terrain to slope failures and can be used for the
estimation of the loss of fertile soil due to slope failures (in agriculture
areas), the selection of new construction sites and road alignments (in
urban or rural areas) and the preparation of landslide prevention,
evacuation and mitigation plans. Natural hazard mapping concerns not only
delineation of past occurrences of natural hazards such as landslide, but it
also includes predicting such occurrences.
Among the earlier research on landslide hazard occurrences which taking
into account the geological inputs was prepared by some researchers [2,3].
Apart from that, a few researchers also found have discussed the similar
matter might be referred worldwide for examples the geotechnical
properties, slope instability, engineering seismology and geological risk
[4-15].
This paper deals with the engineering geological study on 28 selected
critical slopes with the aims of analysis the physical and mechanical
properties of soil and rock, calculate the factor of safety for slopes and to
evaluate the main factors contributing to slope failures. The study area lies
centrally on the weastern coast of Sabah pass through the Crocker Range
roughly about longitude line E 116o 00’ to E 116o 06’ and latitude line N
05o 25’ to N 05o32’ (Figure 1). The mainland part of the Kimanis to
Keningau area is the most accessible. Good networks of sealed and
unsealed roads connecting most of the prime villages around it. Part of the
roads is constructed across the steep, hummocky and rugged slopes,
creating problems of slope and road stability especially during periods of
intense rainfall. Since it’s developed, the problem of slope stability has
adversely affected the use of the road. The Public Work Department of
Malaysia (JKR) authority has started a program of repairing and
rehabilitation of slope failures since 2005 to improve the communication
system. This work is still going on today.
Geological Behavior (GBR)
DOI : http://doi.org/10.26480/gbr.02.2018.01.09
ENGINEERING GEOLOGICAL STUDY ON THE SLOPE FAILURE ALONG THE KIMANIS
TO KENINGAU HIGHWAY, SABAH, MALAYSIA
Rodeano Roslee1,2*, Felix Tongkul 1,2
1Natural Disaster Research Centre (NDRC), Universiti Malaysia Sabah
2Faculty of Science and Natural Resources (FSSA), Universiti Malaysia Sabah
*Corresponding Author Email: rodeano@ums.edu.my
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
ISSN: 2521-0890 (Print)
ISSN: 2521-0491 (Online)
CODEN : GBEEB6

Figure 1: Location of the study area
2. METHODOLOGY
Several classifications can be used to describe slope failures. For this study
in the topics, the types of slope failures were classified according to the
proposals of a researchers [16]. In this system, slope failures are classified
into two main groups: soil slope failures and rock slope failures. Soil slope
failures were divided into slides (T1), slumps (T2), flows (T3), creep (T4)
and complex failures (T5) whereas rock slope failures were divided into
circular (B1), planar (B2) and wedge failures (B3) together with toppling
(B4). In this study, only failures with volume exceeding 10 m3 were
considered, since failures involving smaller volume did not generally
affect the road users. On the basis, the slope failure was divided into three
groups: small (10 – 50 m3), Medium (50 – 500 m3) and Large (> 500 m3).
For each slope failures that were studied (Figure 2), type of failures, the
geometry of the slope, geological background characteristics, weathering
characteristics, ground water condition, discontinuity characteristics,
physical and mechanical of the sliding materials and an interpretation of
the factors causing the failure based on field observations were recorded.
Soil and rock samples from the study area were collected during field
mapping for detailed laboratory analysis.
The laboratory works such as classification tests (grain size, atterberg
limit, shrinkage limit, specific gravity and water content), permeability
test, consolidated isotropically undrained (CIU) test, rock uniaxial
compressive strength and point load test were carried out in compliance
and accordance to British Standard Code of Practice BS 5930-1981 (Site
Investigation), British Standard Code of Practice BS 1377-1990 (Method of
Test for Soils for Civil Engineering Purposes) and ISRM [17-21].
For the soil slopes stability analysis, using the “SLOPE/W” software was
done successfully to determine susceptibility of the slopes to shallow non-
circular slides based on the determination of factor of safety values, which
are common in the study area [22]. The advantage of these methods is that
in its limit equilibrium calculations, forces and moments on each slice is
considered.
Discontinuity orientation data has been collected from ten (10) selected of
rock slope failure by random method. For each rock slope failures that
were studied, the geometry of the slope, dip direction and dip value,
persistence, roughness, unevenness, aperture, infilling material, water
condition, weathering, geological background characteristics, engineering
properties of the sliding materials and an interpretation of the factors
causing the failure were recorded. Determination of discontinuities sets,
critical discontinuities plane, potential mode and rock slope stability
analysis has been performed by RockPack III program [23].
3. LOCAL GEOLOGY AND ENGINEERING GEOLOGY
CHARACTERISTICS
The geology of the study area is made up of sedimentary rock of the
arenaceous Crocker Formation (Late Eocene age) and Quaternary
Alluvium Deposits (Figure 2). Table 1 shows the composite stratigraphic
column of rock units with their water bearing and engineering properties.
The layered nature of the sandstone and shale of the Crocker Formation
are generally oriented between N325E to N010E and show steep dips
(40- 85 degrees) eastward. Large scale folds (> 100 meter wavelength),
faults (several meters wide) and more than four (4) set joints orientation
are common in the study area.
The sandstone-shale contact is easily accessible by water and such contact
seepage may weaken the shale surface and cause slides and falls within
the formation. Interbedded sandstone and shale may also present
problems of settlement and rebound. The magnitude, however, depends
on the character and extent of shearing in the shale. The strength of the
sandstone will also depend on the amount and type of cement-matrix
material occupying the voids. The sandstones are compacted and in g rain
to grain contact with each other. Instead of chemical cement (vein) or
matrix, the pores are filled by finer-grained sands to silt-sized materials or
squeezed rock fragments. The absence of chemical cement reduces the
strength of the sandstone especially when it is weathered or structurally
disturbed.
The shale units have an adequate strength under dry conditions but lose
this strength when wet [8]. During the rainy season, the shale becomes
highly saturated with water which increases the water pressure and
reduces resistances to sliding and falling especially within the sandstones-
shale contact. This condition, in addition to varying amounts of bitumen
and levels of degradation, makes shale unpredictable and unsuitable for
road construction sites. Its unstable nature can be remedied by proper
management of soaking and draining of water from the rock or along the
sandstone-shale contact.
The alluvium is mainly represent unconsolidated alluvial sediment on
river terraces and weathered product materials composed of unsorted to
well-sorted, sand, silt and clay of varying proportions which were derived
from the bed rocks. They occur in irregular lenses varying in the form and
thickness. The alluvium may also consist of very thin layer of organic
matter and characterized as soft, compressible and may be prone to
settlement.
Philippine Sea Plate
Molusca
Eurasian Plate
Sunda Subduction
Study Area
Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.

Figure 2: Geological map with their location of slope failures [24]
Table 1: Local Stratigraphic Column and their lithological characteristics
P
e
t
r
o
l
o
g
y
Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.
Rock
Formation
Litholigic
Units
Average
Thickness
(cm)
General
Character
Water-
Bearing
Properties
Engineering
Properties
Petrology
Sedimentary
Structures
Fossil
Depositional
Mechanism
Depositional
Environment
Alluvium
and
Colluvium
Alluvial
terraces and
flood plains
-
Unconsolidated
gravel, sand and
silt with minor
amounts of clay
deposited along
the rivers or
streams and their
tributaries.
Includes natural
levee and flood
plain deposit.
Gravelly and
sandy, portions
are highly
permeable and
yield large
quantities of
water.
Important to
groundwater
development.
Generally poorly
consolidated.
Hence not
suitable for
heavy structures
and subsidence
under heavy
load.
Angular to
sub rounded
sandstone
blocks in a
silty matrix
- -
Alluvial
terraces and
flood plains
-

Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.
Crocker
Formation
Massive
Sandstone
(Facies B)
100 – 1,000
Light grey to
cream colour,
medium to course
-grained and
some time
pebbly. It is
highly folded,
faulted, jointed,
fractured
occasionally
cavernous,
surfically
oxidized and
exhibits
spheriodal
weathering.
Importance to
groundwater.
Good site for
heavy structures
with careful
investigation.
Stable from
mass movement
and provide
some
modification
like closing of
continuous
structure.
Quarzarenite
and
Sublitharenite
(Immature)
Inorganic
Structures
Pre –
depositional
1. Climbing
Ripple
2. Ripple
Marks
3. Tool Marks
4. Scour Marks
Syn –
depositional
1. Bedding
2. Lamination
3. Graded
bedding
4. Cross
bedding
5. Convolute
lamination
Post –
depositional
1. Slump
structures
2. Soft
sediment
fault
3. Lutite clasts
4. Load
structures
5. Ball and
pillow
structures
6. Water
escapes
structures
Organic
1. Bathysiphon
spp
2. Glomospira
sp
3. Cyclammina
cancellata
(Brady)
4. Haplophragm
oideswalteri
(Grzybowski)
5. Trochammin
oides sp.
Grain flow
deposits
Upper fan to
Middle fan
Thick
bedded
Sandstone
(Facies C)
10 – 50
(Sandstone)
1 – 15
(Shale)
It is a sequence of
interlayering of
permeable
sandstone with
impermeable
shale. The
permeability of
this unit is quite
variable.
Groundwater
in this unit
tends to be
under semi-
confined to
confined
system. Little
importance to
groundwater
provides some
water but not
enough for
groundwater
development.
Dangerous site
for heavy
structures and
high potential
for mass
movement.
Moderately
well sorted to
moderately
sorted
(Mature and
Immature)
High density,
high velocity
turbidity
currents
(Proximal
turbidites)
Outer fan
localized in
channels and
in the
prograding
depositional
lobes.
Thin bedded
Sandstone
(Facies D/E)
3 – 5
(Sandstone)
5 – 10
(Shale)
Waning or
low velocity
turbidity
currents
(Distal
turbidites)
Middle to
outer fan and
particularly
basin plain
Slumped
(Facies F) -
This unit is
composed of two
types of shale red
and grey. It is a
sequence of
alteration of shale
with siltstone of
very fine.
It has no
significant to
groundwater
development
due to its
impermeable
characteristic.
Very dangerous
site for heavy
structures and
the main causes
of mass
movement.
-
Turbidite and
debris flow
sedimentation
Shelf to lower
slope and
partly in the
channels of
inner fan,
middle fan and
basin plain
Red / Grey
Shale
(Facies G)
1 – 2
(Siltstone)
10 – 50
(Mudstone)
-
Structures
Plant remains
Trace fossil
Pre –
depositional
traces
1. Paleodictyo
n minimum
Cosmorhap
he sinuosa
Post –
depositional
traces
1. Post –
depositional
burrow type
1
2. Post –
depositional
burrow type
2
3. Post –
depositional
burrow type
3
4. Post –
depositional
burrow type
4
5. Post –
depositional
burrow type
5
Debris flow
Plain basin,
middle fan and
slope region

4. SLOPE STABILITY ASSESSMENT
In this study, a total of 28 selected critical slope failures were studied and
classified into two main groups: rock slope and soil slope (Figure 2).
Failures in soil slopes (including embankments) are 18 (64 %) (Figure 3)
whereas 10 of all failures (36 %) of rock slope (Figure 4). Soil slope failures
normally involved large volumes of failed material as compared much rock
slopes, where the failures are mostly small. Of the 18 failures in soil slopes,
6 (33 %) are embankment failures making them 21 % of all types of failure.
Results of a detailed analysis of soil slope stability are presented in Table
2. Considering cut slopes, all the major lithologies are involved showing
that this type of failure is mostly controlled by lithology. The failure
volume scale involved generally small to large in size possibly endangering
road users. In term of weathering grades, the materials that underwent
failure were in the ranges from grade IV to VI (Figures 5 to 8). Intense
water runoff and emitted water seepage is the main factor causing failure
with the depth of weathering influencing the volume of material that fails.
It appears that grade IV to grade V materials actually failed with the
overlying grade VI material sliding or slumping down together with this
material during failure. Physical and mechanical properties of 72 soil
samples indicated that the failure materials mainly consist of poorly
graded to well graded materials of sandy clay and clayey silt soils, which
characterized by low to intermediate plasticity content (9 % to 28 %),
containing of inactive to normal clay (0.34 to 1.45), very high to medium
degree of swelling (5.63 to 13.85), variable low to high water content (4 %
to 25 %), specific gravity ranges from 2.57 to 2.80, low permeability (9.66
X 10-3 to 3.32 X 10-3 cm/s), friction angle ( ) ranges from 7.70˚ to 29.50˚
and cohesion (C) ranges from 3.20 KPa to 17.27 KPa. Soil slopes stability
analysis indicates that the factor of safety value as unsafe (0.76 to 0.94).
The presence of ground water, slope angle, removal of vegetation cover,
lack of proper drainage system, artificial changing, climatological setting,
geological characteristics and material characteristics are additional
factors contributing to the failures.
Table 3 shows the results of a detailed analysis of rock slope failures.
Although rock slope failures contributed only 36 % (10 failures) of the
total failures, they involved large volume of weathered and brecciated
rocks (Figures 9 & 10). The main factor contributing to rock slope failures
was the orientation and intensity of discontinuity planes. That is why rock
slope failures occur most frequently along the highway on slate, phyllites,
meta-sediment and sedimentary rocks, which were highly brecciated and
fractured. Generally the failed material underwent only moderately to
completely weathering (grade III to V). The rock properties
characterization for 10 rock samples indicated that point load strength
index ranges from 0.35 MPa to 0.52 MPa (moderately week). Kinematics
slope analyses indicates that the variable potential of circular, planar,
wedges and toppling failures modes as well as the combination of more
than one mode of aforementioned failure. Rock slopes stability analysis
indicates that the factor of safety value as unsafe (0.52 to 0.96). Other
factors contributing to rock slope failure are the presence of groundwater,
climatological setting, joints filling material, high degree of rock fracturing
due to shearing, steep of slope angle, high intensive of faulting and folding
activities and locating at the fault zones area.
Figure 3: Sketch of slope failure showing the failure movement are starting from the hill side to the road and/or village sides through the development of
water runoff (Location: KM 134 (S8)) [24]
Figure 4: Sketch of slope failure showing the movement pattern is to collapse at the head, fall rapidly within narrow tracks, finally dispersing across the
accumulation talus deposits (Location: KM 156 (R8)) [24]
Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.

Table 2: Analysis results of soil slope failures
Type of failure
Shallow slide (T1 –a)
Deep slide (T1 – b)
Location (km)
KM 110
KM 113
KM 117
KM 120
KM 122
KM 129
KM 130
KM 134
KM 138
Slope
S1
S2
S3
S4
S5
S6
S7
S8
S9
G
e
o
l
o
g
i
c
a
l
F
o
r
m
a
t
i
o
n
Crocker
Formation
Trusmadi
Formation
Trusmadi
Formation
Trusmadi
Formation
Trusmadi
Formation
Trusmadi
Formation
Trusmadi
Formation
Crocker
Formation
Trusmadi
Formation
Lithology
Interbedded
Sandstone
& Shale
Sub-
Phyllite
Slate
Sub-
Phyllite
Slate
Sub-
Phyllite
Sub-
Phyllite
Interbedded
Sandstone
& Shale
Slate
Weathering grade
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
Volume (1)
Large
Medium
Large
Large
Small
Large
Medium
Large
Medium
Sand (%)
63 – 65
20 – 23
48 – 51
45 – 48
21 – 24
46 – 50
44 – 45
59 – 61
22 – 24
Silt (%)
5 – 12
52 – 55
18 – 22
13 – 16
54 – 58
18 – 20
16 – 19
6 – 10
13 – 14
Clay (%)
32 – 36
20 – 22
26 – 30
38 – 40
20 – 22
30 – 33
32 – 35
30 – 33
76 – 78
Liquid limit (%)
28 – 31
28 – 32
31 – 33
31 – 33
31 – 34
35 – 37
39 – 41
26 – 30
37 – 39
Plastic limit (%)
15 – 18
13 – 15
14 – 16
16 – 19
12 – 14
22 – 25
16 – 19
10 – 14
21 – 23
Plasticity index
(%)
12 – 16
15 – 19
17 – 19
15 – 17
19 – 22
13 – 15
20 – 23
12 – 18
15 – 18
Liquidity index (%)
- 0.68 to –
0.60
- 0.35 to -
0.30
0.18 to
0.20
- 0.11 to -
0.09
0.14 to
0.18
- 1.08 to -
1.05
- 0.33 to -
0.25
- 0.02 to -
0.01
- 0.88 to -
0.85
Clay activity
0.47 –
0.50
0.98 –
0.99
0.38 –
0.47
0.41 –
0.45
0.53 –
0.55
0.35 –
0.40
1.00 –
1.11
0.87 –
0.91
0.38 –
0.39
Shrinkage limit
(%)
7.51 –
7.95
8.68 –
8.89
8.22 –
10.54
7.28 –
7.55
8.84 –
9.98
6.10 –
7.33
9.16 –
9.86
8.53 –
9.12
5.63 –
6.66
Moisture content
(%)
4 – 8
5 – 8
14 – 17
11 – 14
22 – 25
8 – 10
6 – 10
13 – 15
4 – 8
Specific gravity
2.57 –
2.58
2.60 –
2.62
2.65 –
2.68
2.60 –
2.62
2.60 –
2.62
2.64 –
2.65
2.61 –
2.64
2.61 –
2.63
2.66 –
2.68
Permeability
(cm/s)
(X 10-3)
7.83
3.32
8.47
6.39
5.66
7.61
5.60
5.41
8.78
Cohesion, C
(kN/m2)
9.82
5.13
8.53
9.50
7.76
10.36
17.27
11.43
10.40
Friction angle (o)
29.50
7.70
20.45
25.50
27.70
18.50
23.70
11.29
24.50
Factor of Safety
0.78
0.65
0.92
0.78
0.88
0.95
0.56
0.85
0.98
Main factors
causing failures
SA, W, V, GWL, M, C, G, OBV, DS, EC and AC
Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01- 09.

Table 2: (Cont’d) Analysis results of soil slope failures
Type of failure
Multiple Slump (T2-b)
Complex failure (Slide Flow) (T5 – a)
Complex failure (Slump flow) (T5 – b)
Location (km)
KM 140
KM 142
KM 145
KM 147
KM 152
KM 155
KM 158
KM 162
KM 165
Slope
S10
S11
S12
S13
S14
S15
S16
S17
S18
G
e
o
l
o
g
i
c
a
l
F
o
r
m
a
t
i
o
n
Trusmadi
Formation
Trusmadi
Formation
Trusmadi
Formation
Trusmadi
Formation
Crocker
Formation
Trusmadi
Formation
Crocker
Formation
Trusmadi
Formation
Trusmadi
Formation
Lithology
Sub-
Phyllite
Slate
Slate
Sub-
Phyllite
Interbedded
Sandstone
& Shale
Slate
Shale
Sub-
Phyllite
Slate
Weathering grade
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
IV to VI
Volume (1)
Small
Large
Medium
Large
Large
Medium
Large
Medium
Large
Sand (%)
36 – 39
46 – 47
31 – 33
48 – 51
54 – 58
39 – 42
68 – 70
30 – 33
22 – 26
Silt (%)
22 – 26
10 – 13
9 – 13
7 – 11
21 – 23
18 – 20
12 – 16
6 – 10
10 – 13
Clay (%)
38 – 40
36 – 38
55 – 58
38 – 42
20 – 22
40 – 43
18 – 22
59 – 61
62 – 63
Liquid limit (%)
41 – 44
46 – 49
25 – 29
29 – 32
31 – 33
41 – 43
28 – 30
26 – 30
33 – 38
Plastic limit (%)
22 – 24
19 – 21
15 – 18
13 – 17
13 – 16
23 – 25
16 – 20
10 – 14
16 – 19
Plasticity index (%)
17 – 19
27 – 28
14 – 16
18 – 21
18 – 20
18 – 20
9 – 12
12 – 18
17 – 20
Liquidity index (%)
- 0.85 to -
0.83
- 0.41 to -
0.38
0.09 to
0.15
- 0.26 to -
0.22
- 0.88 to -
0.85
- 0.84 to -
0.78
- 0.62 to -
0.58
- 0.05 to -
0.03
- 0.18 to -
0.14
Clay activity
1.43 – 1.45
0.69 –
0.77
0.42 – 0.47
0.62 – 0.68
0.38 – 0.39
0.43 – 0.49
0.48 – 0.50
0.98 – 1.00
0.46 – 0.52
Shrinkage limit (%)
8.45 – 9.26
12.68 –
13.85
7.98 – 8.33
7.98 – 8.12
5.63 – 6.66
7.98 – 8.65
5.63 – 6.53
8.45 – 8.50
6.34 – 677
Moisture content
(%)
7 – 11
6 – 10
10 – 14
9 – 12
4 – 8
9 – 12
7 – 12
20 – 22
12 – 14
Specific gravity
2.62 – 2.69
2.58 –
2.60
2.74 – 2.80
2.60 – 2.62
2.66 – 2.68
2.64 – 2.68
2.72 – 2.77
2.65 – 2.68
2.68 – 2.72
Permeability (cm/s)
(X 10-3)
5.58
4.62
7.40
7.81
8.78
4.33
9.66
8.54
7.98
Cohesion, C (kN/m2)
15.47
11.43
3.20
10.40
10.40
12.80
9.62
7.20
12.54
Friction angle (o)
22.30
11.29
21.00
24.50
24.50
21.50
21.20
26.30
9.30
Factor of Safety
0.63
0.79
0.91
0.87
0.98
0.58
0.89
0.87
0.89
Main factors causing
failures
SA, W, V, GWL, M, C, G, OBV, DS, EC and AC
Note: (1) Volume: small (10 – 50 m3), Medium (50 – 500 m3) and Large (> 500 m3) and (2) Discontinuity (D), Slope angle (SA), Weathering (W),
Vegetation (V), Groundwater level (GWL), Material characteristics (M), Climatological setting (C), Geological characteristics (G), Over burden or vibration
(OBV), Drainage system (DS), Embankment construction (EC) and Artificial changing (AC)
Apart from that, fieldwork observation indicates that too many cut and
filled slopes was designed does not take into account input or geological
interest. For example most of the slopes were designed too steep, lack of
monitoring on proper drainage system or slope physical state and also we
can found most of the slope cutting surface activities is parallel following
to the strike direction of the sandstone bedding orientation. The trend of
strike and dip of the sandstone bedding orientation along the highway can
be observed in different patterns such low angle dip (030-100/10-20);
medium angle dip (220-280/30-50) and high angle dip (320-345/60-70).
The slope surface orientation was observed is ranging from 210-330 (dip-
direction) and 35-80 (dip) values. Hence, the main factors of slope failures
occurrences along the highway are sourced from the relationship between
the factors of dip-direction slope cutting surfaces with the strike direction
of the sandstone bedding orientation. That is why there were some slopes
in the study area were found in the variable potential of falls, slides and
topples mode types as well as the combination of more than one mode of
aforementioned in the form of the slope failures complex due to this design
negligence described to the above aided by the discontinuities nature
complex very often encountered at study area.
The way groundwater flows; its pressure and gradient at any point within
a slope depend on the local geology. Water plays a very important role in
landslide study. Water can influence the strength of slope forming material
by chemical and solution, increase in pore water pressures and
Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01- 09.

subsequent decrease in shear strength, reduction of apparent cohesion
due to capillary forces (soil suction) upon saturation and softening of stiff
fissured clays, shale and sandstone [4,6,7,14,15]. All slope forming
materials are subject to initial stresses as a result of gravitational loading,
tectonic setting activity, weathering, erosion and other processes [25,26].
Stresses produced by these processes are embodied in the materials
themselves, remaining there after the stimulus that generated them has
been removed (residual stresses). Stress relief many structural features
and stress release activity is an important feature in many rock formations
[27-30]. High lateral stresses have played a crucial role in initiating in over
consolidated of the slope materials.
5. CONCLUSIONS
In light of available information, the following conclusions may be drawn
from the present study:
a. A total of 28 selected critical slope failures were studied and
classified into two main groups: rock slope and soil slope. Failures
in soil slopes (including embankments) are 18 (64 %) whereas 10
of all failures (36 %) of rock slope.
b. Physical and mechanical properties of 72 soil samples indicated that
the failure materials mainly consist of poorly graded to well graded
materials of sandy clay and clayey silt soils, which characterized by
low to intermediate plasticity content, containing of inactive to
normal clay, very high to medium degree of swelling, variable low
to high water content, specific gravity ranges from 2.57 to 2.80, low
permeability, friction angle () ranges from 7.70˚ to 29.50˚ and
cohesion (C) ranges from 3.20 KPa to 17.27 KPa.
c. The rock properties of 10 rock samples indicated that the point load
strength index and the uniaxial compressive strength range
classified as moderately week. Kinematics slope analyses indicates
that the variable potential of circular, planar, wedges and toppling
failures modes as well as the combination of more than one mode of
aforementioned failure.
d. Rock and soil slopes stability analysis indicates that the factor of
safety value as unsafe (0.52 to 0.98).
e. The main factors causing slope failure occurrences in the study area
are natural (geology, meteorology, topography and drainage
system) and human factors (lack of proper planning, human
activities and community’s attitude).
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Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.

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Geological Behavior (GBR) 2(2) (2018) 01-09
Cite The Article: Rodeano Roslee, Felix Tongkul (2018). Engineering Geological Study On The Slope Failure Along The Kimanis To Keningau Highway,
Sabah, Malaysia.
Geological Behavior
, 2(2) : 01-09.