Abstracts – 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.

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.

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.

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.

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.

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.