Geological and soil engineering properties of shallow landslides occurring in the Kutupalong Rohingya Camp in Cox’s Bazar, Bangladesh

Landslides ◽  
2022 ◽  
Author(s):  
A. S. M. Maksud Kamal ◽  
Farhad Hossain ◽  
Md. Zillur Rahman ◽  
Bayes Ahmed ◽  
Peter Sammonds
Keyword(s):  
Shear Strength ◽  
Bulk Density ◽  
Mineralogical Composition ◽  
Fine Sand ◽  
Liquid Limit ◽  
Engineering Properties ◽  
Anthropogenic Factors ◽  
Residual Soil ◽  
Geological Condition ◽  
Residual Soils

AbstractThe Forcibly Displaced Myanmar Nationals (FDMN), historically known as ‘Rohingya’ who fled the 2017 ethnic atrocities and genocide in the Northern Rakhine State of Myanmar, took shelter in Cox’s Bazar District of Bangladesh. The camp network, known as Kutupalong Rohingya Camp (KRC), is situated in the tectonically active tertiary hilly terrain. The KRC has been experiencing hydrometeorological hazards, where landslides are frequent. This study investigated the slopes’ geological condition, engineering properties and human interventions, which influence the landslides. The exposed slopes were relatively high (> 10 m) and steep ranging from 40° to 60° that have numerous polygonal tension cracks and fissures. From the geological and geotechnical aspects, there are three successive units of slope materials: (1) residual soils of sandy silt with clay, (2) highly weathered silty sandstones and (3) shale/clay with silt and fine sand intercalations at the bottom of the slopes. Field observations revealed that most slope failures occurred in the residual soil and weathered silty sandstone units. The residual soils have a bulk density of 1.49–1.97 g/cm3, a liquid limit of 25–48%, a plasticity index of 5–16% and an undrained shear strength of 23–46 kPa. The silty sandstones have a bulk density of 1.44–1.94 g/cm3, an internal friction angle of 34°–40° and a cohesion of 0.5–13 kPa. The mineralogical composition determined by the X-ray diffraction shows low clay mineral content, which does not affect landslides. However, the slope geometry, low shear strength with strain softening properties and torrential rainfall accompanied by anthropogenic factors cause numerous landslides every year. This study will help take proper mitigation and preparedness measures for slope protection in the KRC area and surroundings.

scholarly journals Influence of the structure on the collapse potential and shear strength of a residual soil in the semiarid region of Northeast Brazil

2021 ◽  
Vol 337 ◽  
pp. 01003
Author(s):  
Valteson da Silva Santos ◽  
Allan B.Silva de Medeiros ◽  
Romário S.Amaro da Silva ◽  
Olava F. Santos ◽  
Osvaldo de Freitas Neto ◽  
...  
Keyword(s):  
Shear Strength ◽  
Expansive Soils ◽  
Friction Angle ◽  
Semiarid Region ◽  
Original Structure ◽  
Residual Soil ◽  
Residual Soils ◽  
Strength Parameters ◽  
Effective Measure ◽  
Two Samples

In the last decades, several engineering works have been developed in the Northeast of Brazil, a region marked by the occurrence of collapsible and expansive soils. This work aimed to characterize and study the behavior of two samples of residual soils collected in the municipality of Salgueiro-PE regarding their collapse potentials and shear strength parameters, in natural and disturbed conditions, evaluating the influence of the applied vertical stresses and the structural arrangement in these properties. The results obtained showed that the two samples analyzed show collapsible behavior, however, the observed potential for collapse was lower after the original structure arrangement was undone. From the direct shear strength tests, the strength parameters of the two soils were obtained, which pointed effective friction angle close to 30° and cohesive intercept close to 0 kPa. The destructuring of the samples did not cause a considerable variation in these parameters. Thus, it was possible to conclude that for these samples the microstructure has a predominant influence on the occurrence of collapsibility, but does not have the same relevance on the shear strength, such that the material’s destructuring can be considered as an effective measure to reduce the potential collapse.

Experimental Study on Temperature Effect on Engineering Properties of Clayey Soils

2012 ◽  
Vol 512-515 ◽  
pp. 1905-1918
Author(s):  
Yu Xian Shao ◽  
Bin Shi ◽  
Chun Liu ◽  
Lei Gao
Keyword(s):  
Shear Strength ◽  
Temperature Effect ◽  
Water Content ◽  
Free Water ◽  
Adsorbed Water ◽  
Liquid Limit ◽  
Engineering Properties ◽  
Dry Density ◽  
Clayey Soils ◽  
Increasing Temperature

Temperature significantly influences the engineering properties of clayey soil and this temperature effect usually depends on soil type. In this investigation, laboratorial experiments were conducted on three soils to evaluate the adsorbed water content, Atterberg limits, swelling, shear strength and permeability under different temperatures (5-50°C). The results indicate that liquid limit decreases, swelling increases, permeability increases with increasing temperature. It is fundamentally due to the change of adsorbed water content. Hydrophilic minerals, which contain large amounts of adsorbed water, play an important role in the temperature effect. With the increase of hydrophilic minerals, the temperature effect on liquid limit increases and the effect on swelling ratio decreases. The hydrophilic minerals content also has significant impact on the temperature effect of permeability. With increasing temperature, the adsorbed water is transformed to free water, and then the permeability may increase significantly. The shear strength of clayey soils with higher content of hydrophilic mineral is more sensitive to temperature variation. The cohesive force mainly changes linearly with the temperature. Different phenomena, i.e. thermal-hardening or thermal-softening, was observed on strength behaviour due to different hydrophilic mineral content, moisture content and dry density of sample.

scholarly journals Adsorption of lead (Pb) in strongly weathered tropical soil (Ribeira Valley region - Brazil)

2019 ◽  
Vol 23 (4) ◽  
pp. 385-395
Author(s):  
Carla Patinha ◽  
Mariana Consiglio Kasemodel ◽  
Eduardo Anselmo Ferreira da Silva ◽  
Valéria Guimarães Rodrigues ◽  
Jéssica Pelinsom Marques
Keyword(s):  
Colloidal Particles ◽  
Chemical Properties ◽  
Liquid Limit ◽  
Tropical Soil ◽  
Residual Soil ◽  
Residual Soils ◽  
Initial Concentration ◽  
Local Soil ◽  
Physical And Chemical ◽  
The City

Lateritic soils have been widely used in the construction of landfill base liners for municipal and industrial waste. On the other hand, there is little practice in the use of strongly weathered residual soils for this finality. The use of local soil for the construction of liners in order to waterproof and retain contaminants represents an alternative to control this type of contamination. Thus, the objective of this study was to determine the physical and chemical properties of a strongly weathered tropical soil (residual soil) collected in the city of Eldorado Paulista (Ribeira Valley), and to evaluate the abilityof this soil to adsorb lead (Pb). The contamination of soil and water by Pb due to inadequate mining waste disposal is common in this region. The Pb was adsorbed by the residual soil, mainly at the lowest initial concentrations. When the initial concentration of 20 mg L-1 was used, the adsorption percentage of Pb was 92.5% and when the initial concentration was 100 mg L-1, the adsorption rate was 81.7%. In addition to the retention of Pb, this soil presented the following characteristics which are favorable for using soils in the construction of liners: fine granulometry, liquid limit (LL) of 57%, plasticity index (PI) of 33%, oxidizing medium and the predominance of negative charges on the surface of the colloidal particles. Thus, it is concluded that the weathered tropical residual soil exhibits characteristics that allow it to be used as a liner in the disposal of residues containing Pb.

scholarly journals Shear Strength Deterioration of Compacted Residual Soils under a Wind Turbine due to Drying-Wetting Cycles and Vibrations

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yan-Ming Zhou ◽  
Zong-Wei Deng ◽  
Zi-Jian Fan ◽  
Wen-Jie Liu
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Wind Turbine ◽  
Triaxial Tests ◽  
Residual Soil ◽  
Residual Soils ◽  
Angle Of Internal Friction ◽  
Strength Deterioration ◽  
Deterioration Characteristics ◽  
Compaction Degree

The soil beneath a wind turbine withstands not only environmental impacts but also continuous vibrations transmitted from the superstructure. This paper presents an experimental study of the deterioration characteristics of shear strengths of residual soils affected by drying-wetting cycles and continuous vibrations. A series of triaxial tests were performed on compacted residual soil specimens after various drying-wetting cycles and vibrations. The influences of drying-wetting cycles and vibrations on the shear strengths of residual soils with different compaction degrees were analyzed. The results demonstrate that the shear strength and cohesion of compacted residual soils decreased as the number of drying-wetting cycles increased, and they tended to be stable after three drying-wetting cycles. The angle of internal friction decreased linearly with the reduction of compaction degree but was generally not affected by drying-wetting cycles. The shear strength of compacted residual soils also decreased because of continuous vibrations. After 10000 vibrations, the strength was stabilized gradually. Both the cohesion and angle of internal friction showed dynamic attenuation phenomenon. Finally, a modified Mohr–Coulomb strength equation considering the effects of drying-wetting cycles and vibrations was established. This equation could be used to predict the shear strength of compacted residual soils and further estimate the embedded depth of wind turbine foundations.

Effect of sample size on shear strength of basaltic residual soils

1988 ◽  
Vol 25 (3) ◽  
pp. 478-487 ◽  
Author(s):  
Vinod K. Garga
Keyword(s):  
Shear Strength ◽  
Size Effect ◽  
Key Words ◽  
Strength Testing ◽  
Residual Soil ◽  
Direct Shear ◽  
Limited Data ◽  
Residual Soils ◽  
Shear Tests ◽  
Direct Shear Tests

This paper first provides a brief review of the very limited data available on the size effect on strength of soils. Then it presents the results of an investigation of this effect on the drained strength of two residual soils derived from basalt. The dense basaltic soil, derived from weathering of columnar basalt, is fissured, whereas the vesicular basaltic soil, product of weathering of amygdaloidal basalt, is remarkably free of discontinuities. The results of tests on 500 mm square, 100 mm square, and 63.5 mm diameter direct shear tests, as well as on 36 mm diameter triaxial samples were obtained. The data clearly indicate the significant effect of fissures on the strength of dense basaltic soil, whereas the effect is absent in the vesicular soil. The reduction in strength with size in the former can be attributed almost totally to a loss of the cohesive component of shear strength. In the absence of tests on large-sized samples, a method is suggested to estimate the mass strength of such soils from results of tests on small-sized samples. Key words: fissures, residual soil, size effect, shear, strength, testing.

Assessment of engineering properties of Bangkok clay

2007 ◽  
Vol 44 (2) ◽  
pp. 173-187 ◽  
Author(s):  
Suksun Horpibulsuk ◽  
Satoru Shibuya ◽  
Kittitep Fuenkajorn ◽  
Wanchai Katkan
Keyword(s):  
Shear Strength ◽  
Yield Stress ◽  
Void Ratio ◽  
State Parameter ◽  
Liquid Limit ◽  
Vertical Stress ◽  
Engineering Properties ◽  
Ideal Condition ◽  
Intrinsic State ◽  
Yield State

Due to the effect of structure, Bangkok clay is stable in a metastable state. Its void ratio, e, is the summation of the void ratio sustained by the intrinsic fabric, eR, and the additional void ratio due to the structure, es. The intrinsic state line (eR versus log σ′v, where σ′v is the effective vertical stress) is developed in terms of the void ratio at the liquid limit, eL. At the post-yield state, es is inversely proportional to σ′v. The residual additional void ratio, esr, which cannot be eliminated by the increase in effective vertical stress, is constant at about 0.20 for soft Bangkok clay and 0.12 for medium stiff Bangkok clay. From these findings and the ideal condition of zero compression at the pre-yield state, the field yield stress and field compression curve can be assessed. The undrained shear strength is directly related to the field yield stress, since both reflect the structure. The soil structure does not significantly influence the permeability. The permeability of the clay in structured and destructured states is identical under the same void ratio and can be determined from the generalized state parameter, e/eL. These observations result in a simple and practical method for assessment of the engineering properties of natural Bangkok clay.Key words: Bangkok clay, destructured state, compression, intrinsic state line, permeability, structured state, vane shear strength.

scholarly journals Prior Assessment of Variability in the Geotechnical Properties of Soils for Efficient Infrastructure Management

2021 ◽  
Author(s):  
P.L. Dharamapriya ◽  
H.A.H. Jayasena
Keyword(s):  
Sri Lanka ◽  
Liquid Limit ◽  
Geotechnical Properties ◽  
Engineering Properties ◽  
Residual Soils ◽  
Swell Potential ◽  
Geotechnical Investigations ◽  
Wide Range ◽  
Dry Zone ◽  
Wet Zone

Abstract Advance assessments of variations in geotechnical properties of soils are invaluable in making a crucial judgment of geotechnical engineering projects. It could drive to reduce the number of field and laboratory tests so that efficient management design and construction of infrastructure project outputs can be achieved. In this study, we aim at assessing the geotechnical properties of residual, alluvial, marshy, coastal, and compacted soils within the wet and the dry zones of Sri Lanka. Plastic limit (PL), liquid limit (LL), shrinkage limit (SL), plasticity index (PI), liquidity index (LI), compression index (Cc), swell potential (SP), activity, natural moisture content (NMC) and SPT-N values were either extracted from reports or deduced from formulas and graphs. Wet zone marshy soils (My_W) show highest statistical means for PL (~23%), LL (~40%), PI (~16 %), SL (~20 %), LI (~ 1%), Cc (~ 0.200) and NMC (~ 35%), indicating poor engineering properties. Wet zone residual soils (Re_W) represent a wide range of direct correlations to the parent material. CH, OH, CL and SM soil groups for some My_W show high expansive, while, CL, Pt/CL, OL, SC, SM in My_W, CL, and SC in Re_W and CL in Dry Zone Alluvial Soils (Al_D) display medium expansive. The higher SPT-N values were recorded in the upper 6.00m and between 12.00-16.00m for the shell of earth dams (SED_D) in the dry zone, in contrast to Al_D soils representing higher N values for 6.00-12.00m. Except for marshy soils, no vertical variation for plasticity was observed in others. Since high to medium swell potential in the unsaturated zone is encountered within the upper 1.50m, attention should pay to the My_W. LL and PI of My_W were strongly correlated (R2 = 0.83) so that an equation PI% = -1.91 + (0.46*LL%) could be used to calculate PI. The results provide baseline geotechnical property variations for the five soils in Sri Lanka so that during planning, best-calculated assessment could be achieved which could minimize time and cost for crucial geotechnical investigations.

scholarly journals Tropical Volcanic Residual Soil

2021 ◽  
Author(s):  
Prahara Iqbal ◽  
Dicky Muslim ◽  
Zufialdi Zakaria ◽  
Haryadi Permana ◽  
Arifan Jaya Syahbana ◽  
...  
Keyword(s):  
Research Area ◽  
Liquid Limit ◽  
Primary Forest ◽  
High Plasticity ◽  
Residual Soil ◽  
Residual Soils ◽  
Earth Construction ◽  
Red Color ◽  
Clayey Silt ◽  
Corrosion Of Steel

In West Lampung, Sumatra, Indonesia, tropical volcanic residual soils are formed from weathering of volcanic breccias in hydrothermal alteration areas with a thickness of up to 20 m. This soil has the characteristics of clayey silt, low to high plasticity, brownish-red color, has the potential to swelling, easily eroded, and slide when it is saturated, and contains the minerals kaolinite, halloysite, illite, dickite, nacrite, montmorillonite, despujolsite, hematite, and magnetite. The results showed that this soil can cause corrosion of steel and is widely used by the community as a medium for growing plants and vegetables and as a foundation for infrastructure (for example, houses). The volcanic residual soil of the research area had Low Rare Earth Element (LREE) potential and specific uses. The soil with characteristic low plasticity has Liquid Limit (LL) brine value <50% will be suitable for agriculture purposes, building foundations, and earth construction. At the same time, the other category is soil with intermediate to high plasticity characteristics, which has an Liquid Limit (LL) brine value >50%, was more ideal for the primary forest.

Slope stability in residual soils in Hong Kong

1982 ◽  
Vol 19 (4) ◽  
pp. 521-525 ◽  
Author(s):  
D. J. Sweeney ◽  
P. K. Robertson
Keyword(s):  
Shear Strength ◽  
Hong Kong ◽  
Slope Failure ◽  
Triaxial Tests ◽  
Residual Soil ◽  
Residual Soils ◽  
Long Term Stability ◽  
Granite Residual Soil ◽  
Cut Slopes

A large number of steep, high cut slopes in residual soils exist in Hong Kong and many failures of such slopes have occurred, almost invariably during heavy rainfall. As a result, the long-term stability of many cut slopes is now in question.A brief review of past slope design and slope failure is presented.It has been found that the effective stress shear strength envelope of the Hong Kong soils is curved, particularly at low stress levels, and angles of friction are high. Shear strength results are presented from a series of multistage, consolidated drained, triaxial tests carried out on a typical decomposed Hong Kong granite residual soil. The results of the multistage tests are reviewed to assess the applicability of this type of test to residual soils.The importance of the curved shear strength envelope is discussed in relation to the observed slope failures.

scholarly journals Swelling potential of volcanic residual soils in Sumatra (Indonesia) in relation to environmental issues

2020 ◽  
Vol 8 (4) ◽  
pp. 1-10
Author(s):  
Prahara Iqbal ◽  
Dicky Muslim ◽  
Zufialdi Zakaria ◽  
Haryadi Permana ◽  
Nugroho A. Satriyo ◽  
...  
Keyword(s):  
Soil Surface ◽  
Environmental Issues ◽  
Liquid Limit ◽  
Physical Characteristics ◽  
High Plasticity ◽  
Residual Soil ◽  
Vegetative Cover ◽  
Residual Soils ◽  
Swelling Potential ◽  
Clayey Silt

AbstractSwelling potential characterization of clay-silt soil is an essential issue in stabilization, settlement, consolidation, and land suitability studies. This article attempts to explain the swelling characteristics of soils around the area of West Lampung, Lampung Province, Sumatra, Indonesia, in relation to environmental issues. An investigation in relation to the soil swelling potential was carried out using 15 disturbed soil samples collectd in the study area. The methods used were analyses of clay mineral geochemistry, physical characteristics, and the free swell ratio. These results showed that the soil in the study area was Quaternary tropical volcanic residual soil. These soils were formed in a proximal volcanic hydrothermal alteration environment. The soils of the study area have characteristics of high plasticity, a reddish-brown colour, and are clayey silt grained (MH) (USCS). The soils had loose physical characteristics in dry conditions; however, these soils tends to be plastic and sticky in wet conditions. Evidence of groove erosion was found at the soil surface. Based on XRD analysis, kaolinite, halloysite, and montmorillonite were types of clay minerals found in the soil. The soil had a clay content of 11.05–78.9%, a liquid limit value > 50%, a plasticity index value of 16.7–36.9%, a shrinkage value of 14.24–36.89%, a soil activity of 0.38–2.47; and an FSR value of 0.69–0.95. These characteristics have implications for swelling soil potential. The results showed that the soils in the study area had medium to very high swelling potential. These results suggest a risk of erosion in the area, which could cause soil degradation and a change in water quality. These soils are likely to affect land productivity and aquifer replenishment and will cause negative environmental and economic impacts. Thus, soil improvement techniques are needed. It is important to maintaining vegetative cover these soils and revegetation may be required.

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