Vol. 53 No. 4 December 2022

Unsaturation and Liquefaction: Case Study of Dense Sand

K.H. Tran, S. Imanzadeh, S. Taibi, H. Souli, J.M. Fleureau, M. Hattab, and D.L. Dao

ABSTRACT: The main objective of this paper is studying the behaviour of dense RF Hostun sand subjected to dynamic loading in the triaxial apparatus. The samples with the same initial conditions (water content, void ratio) were prepared by the wet tamping method. After that, the samples were saturated, and then an effective cell pressure of 100 kPa was used to consolidate the sample. To study the liquefaction behaviour of sand, all the samples were subjected to dynamic deviator loading until liquefaction. The experiments show that the cyclic stress ratio needed to liquefy the sample was significantly affected by the saturation degree. All saturated samples were liquefied by the same level of deviator stress; however, the cycle numbers needed to liquefy the samples are different. The results suggest that besides the void ratio and the saturation degree, the sand liquefaction susceptibility may be affected by the different soil fabrics caused by sample preparation technique.

KEYWORDS: Hostun RF sand; Skempton parameter B; Cyclic loading, Liquefaction; Unsaturation.

DOI: 10.14456/seagj.2022.6

Vol. 53 No. 4 December 2022

A Numerical Study on the Shear Strength of Pervious Concrete Column in Weak Ground

Rashma R.S.V, Jayalekshmi B.R, and R. Shivashankar 

ABSTRACT: In this study, the response of pervious concrete column-treated ground under shear loading is examined by employing a series of numerical analyses. The shear behaviour of pervious concrete column-treated ground is compared with stone column-treated ground and weak ground. Two types of analyses were carried out to assess shear strength of the composite ground. Conventional direct shear test model and large shear test models were evaluated using ABAQUS software. The pervious concrete column-treated ground is observed to have greater shear strength than the mere stone column-treated ground. The lateral deflection pattern of the pervious concrete column is also noticed to be very much lesser than conventional stone columns under static shear loading. The overall shear performance of the pervious concrete column-treated ground is found to be improved than the typical stone column-treated ground.

KEYWORDS: Pervious concrete columns, Stone columns, Treated ground, Shear resistance, Numerical analysis.

DOI: 10.14456/seagj.2022.5

Vol. 53 No. 4 December 2022

An Efficient Tool to Determine Undrained Shear Strength of Soft Soils

Dalel Azaiez and Mounir Bouassida

ABSTRACT: Disturbance encountered when testing soft soils both in laboratory and in-situ conditions makes the determination of the undrained shear strength, Su, very challenging. This paper introduces a new tool called “Cylindrical Penetrometer” (CP) to measure the undrained shear strength of soft soils. Description of this tool is given, and the related shear test procedure is detailed. The proposed tool offers the advantage to avoid the disturbance of soft soils before the commencement of the CP test. From recorded measurements and based on considerations of the existing shear tests, a specific method of determination of Su is proposed. The experimental program included laboratory tests by using two sizes of the CP. The recorded results from CP tests, performed on a reconstituted Tunis soft clay, were compared with those obtained from direct shear tests, vane tests, and a consolidated undrained triaxial test. A fair agreement was found between the Cylindrical Penetrometer results with those obtained from the current shear tests.

KEYWORDS: Shear strength, Cylindrical penetrometer, Experiments, Soft soil, Validation.

DOI: 10.14456/seagj.2022.4

Vol. 53 No. 4 December 2022

Analytical Study for a Set of Partially Strengthened End-Bearing Granular Piles

A. Jitendra Kumar Sharma and B. Ashish Solanki

ABSTRACT: In the modern era, the demand of construction is getting high, but land resources are getting exhausted and sometimes left behind option is to use soft soil, which requires ground improvement. Granular Piles (GP) are the most efficient and reasonable key for this problem. In this paper, a comparative study of a set of partly strengthened end-bearing GPs is presented, unfolding the comparison between analytical and rigorous analysis for several normalized aspects like displacement effecting component (DE) for top of GP, displacement interaction factor, percentage load shared by the base (PLSB) and values of normalized shear stress (NSS) across the length of the GP are assessed for end bearing set of two, three, four uniformly placed end bearing piles. The DE, for top of GP is noticed to get decline with the intensification in the values of the strengthening parameters. The interfacial shear stresses get reorganized along the length of the GP.

KEYWORDS: End bearing GP, Displacement effecting component (DE) for top of GP, Displacement interaction factor, Strengthening length fraction from top of GP, Strengthening factor for top of GP.

DOI: 10.14456/seagj.2022.3

Vol. 53 No. 4 December 2022

Inverse Method: Deep Foundation Pit Construction

T. Zhang and D. Pan

ABSTRACT: With the development of urban construction, deep foundation pit projects have been extensively studied. This paper firstly briefly explains the inverse method and then introduces the construction plan and site monitoring plan in a deep foundation pit project in Zhengzhou, Henan Province. The deformation of the surrounding soil of the deep foundation pit was monitored. It was found that the maximum deep horizontal displacement of the foundation pit was 18.39 mm on the north side, 22.98 mm on the south side, 22.67 mm on the east side, and 18.14 mm on the west side; the displacement on the southeast side was larger than that on the northwest side under the influence of the traffic road, and the displacement kept growing with the progress of the construction; the settlement of the surrounding ground surface was between 0 mm and 10 mm; when the soil of the second floor underground started to be excavated, the ground surface settlement accelerated, and the maximum settlement value was – 8.93 mm, which was smaller than the prewarning value. The results verify that the inverse construction method has a small influence on the deformation of the surrounding soil and can be widely applied in actual projects.

KEYWORDS: Inverse method, Deep foundation pit, Soil deformation, Field monitoring, Construction plan.

DOI: 10.14456/seagj.2022.2

Vol. 53 No. 4 December 2022

Water Characteristic Curve for Soils in Kazakhstan

A. Satyanaga, A. B. Ibrahimi, A. S. Mohammad, A.H. Hamdany, M. Wijaya, S. W. Moon, and J. Kim

ABSTRACT: Flux boundary conditions must always be taken into account when analyzing soil behavior under climatic conditions. Since environmental conditions are constantly changing, it is difficult to predict the expansive behavior of the soil and work with it. The soil-water characteristic curve (SWCC) of soils is one of the most important indicators that carries information on the interaction of the air, liquid, and solid phases of soils. Even though large databases of various soil characteristics have now been created in Kazakhstan, many territories remain unexplored with the construction of the main soil-water characteristics curve since the study and construction of these functions can take a long time. The main objective of this study is to construct the SWCC for various soil types throughout Kazakhstan. To achieve it, soil data were collected from the available geotechnical investigations to draw up the soil profile and its properties in the studied regions. The results of the analyses indicate that soils in Kazakhstan can be divided into three main regions. The typical SWCC for different soil classifications at different regions is generated as a result from this study.

KEYWORDS: Soil-water characteristic curve, Unsaturated soil mechanics, Soil properties, Soil profile.

DOI: 10.14456/seagj.2022.1

Vol. 53 No. 4 December 2022 ISSN 0046-5828

Sponsored by: Asian Institute of Technology

Contents and Abstracts

Vol. 53 No. 3 September 2022

Predicting the UCS of Lime‒Stabilized Clayey Soils

B. Sari-Ahmed, Ghrici, and K. Harichane

ABSTRACT: This study was made in order to develop a statistical model for predicting the unconfined compressive strength (UCS) of lime-stabilized clayey soils. The obtained results showed that the developed model (UCS‒Model) is very efficient and can be used as a reliable tool for predicting the UCS of lime‒stabilized clayey soils. Indeed, both the (F-test) and (t-test) showed that the significance value of UCS‒Model was found to be less than 0.05 which indicates that the lime content and curing time significantly contribute to the constructed model and lead to a better prediction of UCS. In addition, the comparison study between predicted values and experimental data indicated that the UCS model can be reasonably applied to explain the effect of lime content below 10%, and curing time between 0 and 90 days on UCS of clayey soils and to design new mixtures without making an experimental study.

KEYWORDS Clayey soils, Lime, Unconfined compressive strength (UCS), Curing time, Statistical model.

DOI: 10.14456/seagj.2022.10

Ozcelik and F. Tuzlu

ABSTRACT: The design and construction of tunnels is among the most specialized fields in underground engineering. There are various uncertainties during tunnel excavation. Predictable and unpredictable uncertainties are important sources of risk in tunnel engineering. The effect of uncertainty on risk assessment and decision-making is therefore provided priority, particularly for tunnel projects where predictable uncertainty is often the primary cause of risk. First phase of the Kabatas-Mahmutbey tunnel excavation, some collapses occurred due to uncertainties in different parts of the tunnel route. Regardless, Kabatas-Mahmutbey metro line, which is 24.5 km long and consists of 19 stations, was planned to be operational in the first quarter of 2020. For this purpose, electrical and mechanical tests were successfully continuing within the scope of the project. In addition, the signalling works of the metro line were near to the end. All technical uncertainties and risks were thought to be circumvented. In the last phase of the project, Coronavirus Disease 2019 (COVID-19) was encountered as unpredictable uncertainty. Unfortunately, due to COVID-19, the work in the project has been postponed to a later date. With the commissioning of the metro project, which will breathe the traffic of Istanbul upon commissioning, it is foreseen to carry 500 thousand passengers a day.

KEYWORDS: Uncertainty, Tunnel, Construction, 3D Modelling, COVID-19.

Gellan Gum for Strengthening Bentonite-Sand Slurry

T.P.A. Tran, T. Katsumi, and T.N. Tran

ABSTRACT: The strengthening ability associated with adding a gellan gum as an additive to bentonite slurry for use in coating soil surfaces was studied. Bentonite powder was mixed with hot gellan gum hydrogel (i.e., at 200 °C) to different gellan gum concentrations (i.e., 0, 3, 4, 5, 6, and 7% of the mass of distilled water). A series of unconfined compressive strength tests were conducted on gellan gum-bentonite mixtures subjected to various thermal curing conditions. The shrinkage behavior was observed during the thermal curing process. The research also studied the sand size particle effect on the strength and volume change of the dried gellan gum-modified bentonite. The test results showed the soil strengthening effect of adding gellan gum to bentonite slurry which was then added it to bentonite/silica sand mixtures.

KEYWORDS: Gellan gum, Bentonite, Silica sand, Unconfined compressive strength, Thermal curing process. 

Comparative Study on Strength and Permeability of Siliceous Sand Treated by MICP and Cement Grouting

Hai-lei Kou, Wang-xiang Hou, Peng-peng Ni, and Jia He

ABSTRACT: Cement and other chemical materials are widely used as additives in soil improvement. Microbially induced calcite precipitation technology has been used in soil improvement as the advantage of green and environmental protection. In this study, the potential of using microbially induced calcite precipitation (MICP) technology replaces cement for treating siliceous sand is presented. A series of laboratory tests were carried out to assess the unconfined compressive strength (UCS) and permeability of microbial-reinforced sand and cement-reinforced sand. The results indicated that, for the experimental siliceous sand with a small particle size (0.63-1.25 mm), the average UCS of the microbial-reinforced sand is significantly higher than that of the cement-reinforced sand under the condition of curing for 7 days, and the quality of cement-reinforced sand is affected by the water-cement ratio. The permeability coefficient of microbial-treated sand is also significantly reduced, which are 0.0007 times and 0.05 times that of pure sand and cement-reinforced (w/c = 2:1), respectively. The porosity reduction of the sample after microbial grouting is up to 13.6%, which is also significantly higher than cement-reinforced. The microstructure study shows that calcite crystals can not only be widely attached to the surface of sand particles, but also better penetrate into the voids between sand particles, formed more effective ways of connection and make more effective bonding. It explains why microbial-reinforced sand has higher unconfined shear strength and lower permeability coefficient than cement-reinforced sand.

KEYWORDS: Siliceous sands, MICP, Cement grouting, Unconfined compressive strength, Coefficient of permeability.

Predicting the UCS of Lime‒Stabilized Clayey Soils

B. Sari-Ahmed, Ghrici, and K. Harichane

ABSTRACT: This study was made in order to develop a statistical model for predicting the unconfined compressive strength (UCS) of lime-stabilized clayey soils. The obtained results showed that the developed model (UCS‒Model) is very efficient and can be used as a reliable tool for predicting the UCS of lime‒stabilized clayey soils. Indeed, both the (F-test) and (t-test) showed that the significance value of UCS‒Model was found to be less than 0.05 which indicates that the lime content and curing time significantly contribute to the constructed model and lead to a better prediction of UCS. In addition, the comparison study between predicted values and experimental data indicated that the UCS model can be reasonably applied to explain the effect of lime content below 10%, and curing time between 0 and 90 days on UCS of clayey soils and to design new mixtures without making an experimental study.

KEYWORDS Clayey soils, Lime, Unconfined compressive strength (UCS), Curing time, Statistical model.

Deterministic and Probabilistic Approach of Seismic Slope Stability Analysis – A State-of-The-Art Review

Partha Pratim Boruah and Arunav Chakraborty

ABSTRACT: For a slope to be safe, it must always have a factor of safety (FOS) against sliding greater than one. If the slope simply experiences elastic deformation, then only the above condition is applicable. However, in the event of a severe seismic motion, the slope deformation may overtake the elastic limit, resulting in permanent displacements. In such a scenario, the FOS considering static output is irrelevant and have to consider seismicity. As a result, the relevance of the stability of the soil slope under seismic loading conditions is growing in the field of geotechnical engineering. A lot of studies have investigated the stability of a slope under static and seismic stress conditions. This paper reviewed various studies where the seismic loading consideration is exits. The purpose of this paper is to know the existing soil slope stability techniques which utilize several dynamic methods which includes finite elements approach, limit equilibrium approach, strength reduction approach, discrete element approach, Newmark’s approaches etc. The deterministic approach and the probabilistic approach are used to conduct the literature review.

KEYWORDS: Seismic analysis, Dynamic analysis, Factor of safety, Slope stability.

Vol. 53 No. 3 September 2022

Deterministic and Probabilistic Approach of Seismic Slope Stability Analysis – A State-of-The-Art Review 

Partha Pratim Boruah and Arunav Chakraborty

ABSTRACT: For a slope to be safe, it must always have a factor of safety (FOS) against sliding greater than one. If the slope simply experiences elastic deformation, then only the above condition is applicable. However, in the event of a severe seismic motion, the slope deformation may overtake the elastic limit, resulting in permanent displacements. In such a scenario, the FOS considering static output is irrelevant and have to consider seismicity. As a result, the relevance of the stability of the soil slope under seismic loading conditions is growing in the field of geotechnical engineering. A lot of studies have investigated the stability of a slope under static and seismic stress conditions. This paper reviewed various studies where the seismic loading consideration is exits. The purpose of this paper is to know the existing soil slope stability techniques which utilize several dynamic methods which includes finite elements approach, limit equilibrium approach, strength reduction approach, discrete element approach, Newmark’s approaches etc. The deterministic approach and the probabilistic approach are used to conduct the literature review.

KEYWORDS: Seismic analysis, Dynamic analysis, Factor of safety, Slope stability.

DOI: 10.14456/seagj.2022.11