Effect of Sand and Sand-Lime Piles on the Behavior of Expansive Clay Soil

Mohamed Hussein,Wanjei Cho

doi:10.1155/2021/4927078

Abstract

Expansive clay soil causes serious problems to many structures due to its swelling and shrinkage during wet and dry seasons. With the existence of expansive soil in Ahkmim new city, Sohag governorate, Egypt, some light buildings, road pavements, and buried pipelines have shown some damage. To avoid such damage, prior to construction, expansive clay soils should be stabilized. Different methods are available to improve the engineering properties of these soils such as densification, chemical stabilization, reinforcement, and techniques of pore water pressure reduction. The chemical stabilization of clay using lime is one of the widespread methods that can be used to improve the behavior of expansive clay soil. This study aims to investigate the effect of both sand and sand-lime piles on the behavior of expansive clay soil. A series of laboratory tests were carried out using the conventional Oedometer apparatus. Sand piles with different replacement area ratios (RARs) (4.68%, 10.16%, 24.6%, 35.84%, and 56.9%) were used. Also, sand piles stabilized with different percentages of lime (3%, 6%, 9%, 12%, 15%, and 20%) and with a replacement area ratio of 35.84% were used. The experimental results showed there is a significant improvement in reducing the swelling potential of expansive clay soil reinforced with sand or sand-lime piles. This improvement increases with the increase of both replacement area ratio and lime content.

Highlights

Expansive clay soils are normally accompanied by volumetric changes when subjected to changes in water content due to seasonal water variations. ese soils have a good bearing capacity and low settlement in dry conditions
The swelling reduction factor increases significantly with the increase of replacement area ratios (RARs), where it reaches 8.3%, 17.026%, 25.898%, 33.657%, 43.57%, and 61.06% with RAR being equal to 4.68%, 10.16%, 15.9%, 24.6%, 35.84%, and 56.94%, respectively. e prediction model has been developed for the change in swelling potential reduction factor with various RARs. predicted as follows: SPRF(%) 1.181RAR(%), R2 0.9841
E proposed equation (6) has been verified with the results obtained by Hergul [51] as shown in Table 6. is table shows that the proposed equation for predicting the swelling potential reduction factor for expansive clay soils reinforced with sand piles can be applied confidently

Summary

Introduction

Expansive clay soils are normally accompanied by volumetric changes when subjected to changes in water content due to seasonal water variations. ese soils have a good bearing capacity and low settlement in dry conditions. Is research aims to take the advantage of lime to reduce the swelling of expansive clay soils as proven from different previous studies and improve the stiffness of sand piles as well. E size of the sand pile and increasing its stiffness by mixing it with hydrated lime play an important role in changing the behavior of expansive clay soil. These two aspects are varied in the present work, and the influence of the sand pile diameter, which is presented here by replacement area ratio (RAR), and the lime content on the swelling of expansive clay soil was studied. These two aspects are varied in the present work, and the influence of the sand pile diameter, which is presented here by replacement area ratio (RAR), and the lime content on the swelling of expansive clay soil was studied. e details of the experimental program, the results of the tests, and the conclusions drawn from the study are described below

Experimental Program

Tests Setup and Procedure

Results and Discussion

Oedometer Test Results

Conclusions