Fig 6 - available from: Geoenvironmental Disasters
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a Photographs showing the nature of infrastructural collapse on cohesionless soils in the study area. b Photographs showing the nature of infrastructural collapse on cohesive soils in the study area
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Abstract Structural failure of buildings, roads, and other infrastructures has led to the loss of lives and monumental damage to the economy. In developing countries such as Nigeria, the failures are always attributed to the nature/type of soils in the area without considering other factors. With the increase in civil engineering constructions and...
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Citations
... There are several geophysical approaches for the evaluation of in-situ Vp and/or Vs and obtaining a 1D Vs profile or 2D Vs cross-sections versus depth (e.g., Al-Saigh and Al-Heety, 2013; AL-Saigh & AL-Heety, 2018; Abdelrahman et al., 2021a;2021b). This important parameter can be precisely obtained using surface geophysical methods to evaluate the appropriateness of surface materials for roads, building constructions, and foundations like MASW methods (Socco and Strobbia, 2004;Fnais et al., 2015;Abd El-Aal et al., 2016;Al-Amri et al., 2016;Rehman et al., 2016;Aldahri et al., 2017;Alamri et al., 2020;Igwe and Umbugadu, 2020;Mogren et al., 2020;Naji et al., 2020;Al-Heety et al., 2021;Almadani et al., 2021;Alzahrani et al., 2021;Abdelrahman et al., 2021c;El-Raouf et al., 2021;Abdallatif et al., 2022;Al-Heety et al., 2022;Ayele et al., 2022;Ferguson and Gautreau, 2022;Jusoh et al., 2022). This method is dependable, non-invasive, and cost-effective in engineering practices. ...
The site characterization process is vital for the engineering structures and earthworks. In the current study, a Multi-Channel Analysis of Surface Waves (MASW) was carried out in western Riyadh City, Saudi Arabia. This aimed to determine subsurface geology, material stiffness, and potential weak zones approximately down to a depth of 30 m, and to propose the suitable seismic site characterization for precise foundation design. A total of 30 MASW lines were executed utilizing the Geode digital seismograph equipped with a 24-geophone array of 4.5 Hz. The data acquisition, processing, and inversion were meticulously calibrated to derive shear velocities representing subsurface geological conditions. The Vs30 map, based on estimated values ranging from 443.71 m/s to 639.78 m/s for soil, was prepared for the area. The results of the 1D and 2D Vs profiles tinted small Vs values at shallow depths. The resulting geological model is composed of sand, gravel, moderately weathered limestone, and hard limestone sequence. Analysis of shear wave velocities shows variations, indicating low shear velocity (representing sediments or rocks of low stiffness) juxtaposed with higher velocity layers (indicating rocks of higher stiffness) at depths greater than 10 m. This could imply the presence of a cavity or weak zone. The topmost shear wave velocity zone indicated materials with low Vs values (ranging from 180 m/s to 360 m/s), predominantly associated with stiff materials such as silty sand, gravel, and sandy deposits. The subsequent zone, with 3 to about 10 m depth, was characterized by medium to very dense soil with shear wave velocity values ranging from 360 m/s to 760 m/s, attributed to layers of silty clay and silty sand. At approximately 12 m, a high shear velocity layer (ranging from 760 m/s to 1,500 m/s) was identified, extending to a maximum depth of 22 m, potentially indicative of less weathered or fractured bedrock associated with limestone. While the deepest layer, with very high shear velocity (exceeding 1,500 m/s) beyond 22 m, indicated bedrock associated with hard limestone. The average Shear-wave velocity of soil for the whole study area (Vs30 = 551.2 m/s) suggests that the site can be classified as Class C (Very Dense Soil and Soft Rock) according to the National Earthquake Hazard Reeducation Program NEHRP (National earthquake hazards reduction program, 2001). These results will support, to a great extent, the design of engineering structures in the area of study.
... Clayey soils frequently have weak strength properties as shown in - Table 1, and present substantial building challenges that cause significant settlements that are harmful to structures built on top of them [1]. Construction of infrastructures on un-stabilized expansive/clayey soil has contributed to the loss of properties, lives and causes financial instability in many homes today [2]. In order to help mitigate some of those live threatening issues, engineers have introduced several methods of improvement or stabilization of cohesive/expansive soil by adding additives and bounding materials like cement, lime etc. for load bearing [3]. ...
... Fly ash is noted for the improvement of clayey soil by reducing the level of swelling [7]; moisture content [8]; and increase the soil's UCS [2]. Not only that fly ash improves clay soil, using rice hush ash also increases the Unconfined Compressive Strength of clayey/expansive soil [9]; It decreases the MDD as well [10]. ...
Infrastructural development on unstable clayey soil has resulted to the damage of buildings and roads, the loss of lives, and financial instability in many projects including both vertical and horizontal structures due to the incapability of clayey soil to withstand certain magnitude of loadings. Furthermore, the deposit of materials that are left-over in open areas has also become an environmental challenge for residents in many communities. This review elaborates on the effect of waste materials—SDA (sawdust ash), FA (fly ash), and RHA (rice hush ash)—on the shearing strength of clayey soil as agents for stabilization. The study covers significant books on stabilizing clayey soil with additives as well as high indexed research articles that were published from 1998 to 2023. The findings show that, mixing the ash of sawdust with natural clay soil at the peak values of four (4) percent to seven point five (7.5) percent carries up the UCS (Unconfined Compressive Strength), the MDD (Maximum Dry Density), the CBR (California Bearing Ratio), and lowers the soil’s swelling, Optimum Water Content or OMC and Liquid Limit (LL). Similarly, the mixture of FA and clay soil at the optimum values ranging from 9 to 25%, raises the clayey soil’s UCS, MDD, and CBR while lowering its swelling potential, OMC, and LL. Additionally, the UCS, MDD and CBR increases, and the swelling, OMC, and LL reduce at the optimum value of added rice hush ash ranging from 10 to 20%. Thus, it is established that the addition of sawdust, fly, and rice hush can enhance clayey soil’s engineering properties.
... Soil possesses a multitude of engineering properties that dictate its suitability for diverse engineering applications (Ebuzoeme, 2015). Poor knowledge of the soil properties stands as one of the primary causes of structural failures (Igwe and Umbugadu, 2020). Soils are produced mainly through rocks weathering, and partially through decomposition of organic materials. ...
The research investigated the influence of green ash on the engineering properties of fine-particle soils, with a focus on their suitability in construction and electronic industries. The soil underwent treatment with plantain peel ash (PPA) at varying concentrations of 2, 4, 6, 8, and 10% by mass of the dried soil, and was followed by a curing period of 21 days. Thereafter, the California Bearing Ratio (CBR), free swell index (FSI), dielectric constant (ε'), dielectric loss (ε''), and relaxation time (τ) values were measured following ASTM-approved guidelines. The results revealed that the PPA had substantial influence on the soil CBR and FSI parameters. The soil CBR increased from 4.39 to 16.62%, while the FSI declined from 15.27 to 8.77%, as the PPA quantity increased linearly from 0 to 10%. Regarding the soil dielectric parameters, the results depicted that the ε', ε'' and τ increased unevenly from 4.27 to 7.11, 1.01 to 1.85, and 4.18 to 4.6, respectively, when the concentration of the PPA was increased evenly from 0 to 10%. The improvements noted due to the PPA presence in the soil, impacting both its geotechnical characteristics and specific dielectric properties, indicate the potential for utilizing PPA in the production of eco-friendly electronic components.
... The expansive nature of these soils has led to significant damage to buildings and infrastructure. For example, in the United States alone, expansive soils annually cause destruction exceeding 15 billion dollars [5]. Due to the potential for property loss, it is essential to stabilize expansive soil before using it in the construction of buildings and roads. ...
Expansive soils are known to swell and shrink with moisture content changes, rendering them unsuitable for construction without proper stabilization. Cement and lime have conventionally served as common additives for soil stabilization. However, in Uganda, the escalating costs of these additives accentuate the need for alternative solutions. Therefore, this research attempts to investigate the viability of sawdust ash, an affordable agricultural waste, as an effective stabilizer for expansive soils. Through systematic experimentation, various percentages of sawdust ash (ranging from 0% to 10%) were introduced into the soil matrix. The objectives of the study were achieved through a series of laboratory tests, including gradation analysis, Atterberg limit determination, compaction, and California Bearing Ratio (CBR) test. The findings revealed the soil is clay with high plasticity, emphasizing the need for stabilization. Importantly, the addition of sawdust ash resulted in a substantial reduction in the plasticity index, from 35% to 16%, at 0% and 10% sawdust ash content, respectively. Furthermore, the incorporation of sawdust ash led to an increase in the maximum dry density and a reduction in the optimum moisture content as its proportion was augmented. Notably, with 6% sawdust ash content, the CBR value reached its highest point at 14.4%. These outcomes reveal the potential of sawdust ash as an economically attractive alternative to traditional stabilizers such as cement and lime. This research contributes valuable insights to the field of soil stabilization and offers a sustainable solution that addresses both economic and environmental concerns in construction practices.
... The magnetic method uses the magnetization contrasts between different lithologies to examine environmental or geologic subsurface problems of various kinds. These problems include subsurface elements and mineral and ore detection (Al-Garni, 2010;Dar and Bukhari, 2020;Mehanee et al., 2021;Ben et al., 2022a;Saada et al., 2022;Ekwok et al., 2023), hydrocarbon exploration (Osinowo and Taiwo, 2020), archaeological investigation (Essa and Abo-Ezz, 2021), geotechnical engineering (Igwe and Umbugadu, 2020), cave discovery (Orfanos and Apostolopoulos, 2012) and geothermal exploration (Abraham and Alile, 2019). Inversion of magnetic data for arbitrarily complex structure is an ill-posed and non-unique problem (Utsugi, 2019). ...
... Hence, the construction of engineering structures on such soil is a challenging task and can be harmful [3], facilitating crack formation, differential settlement, and sudden failure due to their changing behaviour [4], thus inducing economic concerns. For example, the annual damage cost associated with the reversible shrink-swell behaviour of expansive soil exceeds £400 million in the UK [5], and 15 billion in the USA [6]. However, replacement of the sub-grade layer with high-bearing capacity soil is considered costly and time-consuming [7]. ...
Chemical soil stabilisation, a conventional soil treatment technique, is a function of several variables including the mineralogical compositions of soil, the oxide contents of the stabiliser, the sulfate concentration of soil, and the water content used for compaction, among other variables. This paper reports an experimental study investigating the impact of variation in the moisture compaction content, mixing method and specimen size on sulfate soil stabilisation with the co-addition of lime (L) and silica fume (S). A series of artificially gypsum-dosed kaolin specimens were prepared using a binder composition of 3L-7S, two different moisture contents (31 and 33%), two different mixing methods (dry mixing method-DM and slurry mixing method-SM) and two different specimen dimensions; one with 100 mm in height and one with 19 mm in height. Thereafter, a set of physico-mechanical engineering tests including the unconfined compressive strength (UCS) test, linear expansion test and swelling potential test were conducted to examine their physical and mechanical behaviour. The finding of this study indicated that the use of SM instead of DM induced a compromise on both the expansion and UCS performance due to the clumping and the heterogeneity of the formed hydrates. As for the moisture content variation, the result showed that the higher moisture content of 33% yielded a better expansion and lower UCS performance due to the enlargement of voids which reduces the robustness against loading and facilitates the accommodation of ettringite.
... Geotechnical properties are major soil engineering properties that are considered during the design and construction of civil engineering structures. Soil with poor geotechnical properties tend to fail easily; hence it is not suitable for building structural works, without adequate stabilization prior to its utilization (Roy and Bhalla, 2017;Ugwuanyi and Onyelowe, 2019;Igwe and Umbugadu, 2020). Increment in structural failures in Nigeria, is partly attributed to poor soil conditions (Awoyera et al., 2021). ...
Detailed investigation of the geotechnical properties of borrow pits soils, used for road and other construction works in major Niger Delta communities of Nigeria was carried out. The particle size distribution, specific gravity, liquid limit (LL), plastic limit (PL), plasticity index (PI), maximum dry density (MDD), optimal moisture content (OMC), free swelling index (FSI) and Californian bearing ratio (CBR) of the sampled soil were measured in accordance with the British Standard (BS) code and America Standard Testing Material (ASTM) code. Based on the Unified Soil Classification System (USCS), the borrow pits soil can be classified as poorly graded sand with clay. Also, the results depicted that the borrow pits soil Specific gravity, LL, PI values and PL valued ranged from 2.6-2.71, 21.1% -34.08%, 6.29%-13.58% and 15.81% - 20.23%, respectively. OMC, MDD and CBR ranged from 14.53%-15.17%, 1.53 kg/m 3 -1.69 kg/m 3 and 20.19% -47.15%, respectively. The study affirmed that some of the soils can be useful for the construction of roads and other civil engineering structures, without stabilization.
... An ample evaluation of geologic and geotechnical subsurface conditions in an intended engineering site is critical for the secure design of building structures, to avert the disastrous consequences of structural failure and collapse prevalent of late. In subsoil evaluation, joint efforts must be decided to resolve the depth to competent layers across the intended site, to safeguard the durability of civil engineering structures i.e. buildings, bridges, roads and other infrastructures [1,2] . On the 1st of November 2021, it was reported that a 21-storey building on Gerard Road, Ikoyi, Lagos State collapsed killing many people, due to lack of quality assurance/control, poor management of the project and negligence by agencies responsible for approval and supervision of the building project [3] . ...
... In each case, the water content (Wc) for each blow was determined using the formula: (1) For soil sample-1 collected from the borehole (BH-1) the number of blows/drops used was 6, 14 and 34 blows and water content was determined for each blow respectively. In soil sample-2 collected from the borehole (BH-2) the number of blows/drops used was 13, 23 and 54 blows and water content was determined for each blow while in soil sample-3 collected at borehole (BH-3) the number of blows/drops used was 18, 23 and 30 blows respectively and water content were determined for each blow. ...
... Geotechnical analysis of soil samples is a necessary requirement for an engineering site characterization program. The water content of the soil samples was evaluated using Equation (1). The results of water content for the three (3) soil samples are presented in Tables 3 to 5. From the plot of moisture content against the number of blows for soil sample-1 (Figure 10), the moisture content corresponding to 25 blows on the logarithmic axis is the liquid limit, which was read approximately as 13%. ...
In the design of building structures, joint efforts must be decided to resolve the depth to competent layers across the intended site, and periodic subsidence monitoring and deformation assessment of all buildings, specifically high-rise buildings, should be a regular practice, to safeguard the durability of civil engineering structures, to avert the disastrous consequences of structural failure and collapse prevalent of late. It was this extremity that necessitated the adoption of an integrated methodology which employed DC resistivity tomography involving 2-D and 3-D techniques and geotechnical-soil analysis to evaluate subsoil properties for engineering site investigation at Okerenkoko primary school, in Warri-southwest area of Delta State, to adduce the phenomena responsible for the visible cracks/structural failure observed in the school buildings. Rectilinear set of 2-D resistivity data consisting of five (5) parallel and five (5) perpendicular lines were obtained in a 100 x 80 m2 rectangular grid using the Wenner array. Thirteen (13) Schlumberger soundings were also obtained on the site with half-current electrode separation of 200 m. The results brought to light the geological structure beneath the subsurface, which consists of four geoelectric layers identified as top soil, dry/lithified upper sandy layer, wet sand (water-saturated) and peat/clay/sandy clayey soil (highly water-saturated). The deeply-seated peat/clay materials (ρ ≤ 20 Ωm) were delineated in the study area to depths of 17.1 m and 19.8 m from 2-D and 3-D imaging respectively. The dominance of mechanically unstable peat/clay/sandy clay layers beneath the subsurface, which are highly mobile in response to volumetric changes, is responsible for the noticeable cracks/failure/subsidence detected on structures within the study site. The DC resistivity result was validated using geotechnical test of soil samples collected from boreholes covering the first 8.0 m on three of the profiles. Atterberg’s limits of the soil samples revealed plasticity indices of zero for all samples. Thus, the soil samples within the depth analyzed were representatives of sandy soil which does not possess any plasticity and their plasticity index is taken as zero. These findings apparently justify the subsoil conditions defined in the interpretation of 2-D and 3-D resistivity imaging data. 3-D images presented as horizontal depth slices revealed the dominance of very low resistivity materials i.e. peat/clay/sandy clay within the third, fourth and fifth layers at depths ranging from 5.38-8.68 m, 8.68-12.5 m and 12.5-16.9 m respectively. Hence, 3-D tomography amplified the degree of accuracy of the geoelectrical resistivity imaging. Resistivity contour maps of second, third and fourth layers for VES 1 to 13, displayed low resistivity direction predominantly towards the northeastern part of the site, and signifies that rocks within the northeastern part have low resistivity values, which connotes high porosity and establishes the groundwater flow trend in the study area. The methods employed in this study justifiably gave relevant information on the subsurface geology beneath the study site and its suitability for engineering practice. Thus, it is suggested that these methods should be appropriated as major tools for engineering site assessment projects and groundwater future studies.
... Several studies have used integrated geophysical and geotechnical investigations to characterize its suitability of the near-surface materials for road, building constructions, and foundation [10][11][12][13]. On this regards, multichannel analysis of surface waves (MASW) are widely used to measure the shear wave velocity (Vs) of near-surface materials as these methods are reliable, noninvasive, and low-cost procedures in engineering applications to identify potentially unsuitable geological conditions, determine small-strain stiffness of soil and rock, foundation instability analysis, and know site classes [14][15][16]. ...
... Several studies have used integrated geophysical and geotechnical investigations to characterize its suitability of the near-surface materials for road, building constructions, and foundation [10][11][12][13]. On this regards, multichannel analysis of surface waves (MASW) are widely used to measure the shear wave velocity (Vs) of near-surface materials as these methods are reliable, noninvasive, and low-cost procedures in engineering applications to identify potentially unsuitable geological conditions, determine small-strain stiffness of soil and rock, foundation instability analysis, and know site classes [14][15][16]. ...
Site characterization is a prerequisite for the successful and economic design of engineering structures and earthworks by providing geological information for any proposed project. Until now, no detail study has been carried out on the site characterization and classification using shear wave velocity (Vs) up to the top 30 m depth in Hawassa town. For this study, multichannel analysis of surface waves (MASW) was used to determine the variation of Vs for a proper civil engineering design in the town. In addition, vertical electrical sounding (VES) and standard penetration test (SPT) were employed to characterize the near-surface materials. The Vs30 map was prepared for Hawassa town using the estimated Vs30 values which ranges from 248.9 m/s to 371.3 m/s while the SPT-N values were ranges from 5bpf to 50bpf. The correlation of Vs and SPT-N values has been done by considering both corrected and uncorrected SPT-N values. The VES result showed that groundwater is found at a shallow depth. The correlation of Vs and SPT-N value was validated using regression model. The 1D Vs profile and 2D cross-section showed low Vs at a shallow depth. The near-surface soils of the town are classified based on the Vs30 as site class C (stiff soil and soft rock) and D class (stiff soils) according to the NEHRP (Natural Earthquake hazards Reduction Program) and as subsoil classes B and C according to the Eurocode 8. The geotechnical tests also showed that the soils in the study area are silty sand, sand and silty sand with some gravel. The low Vs values observed at a shallow depth should be given much attention during foundation design for the stability of civil engineering structures.
