Experimental study on the coefficient of lateral earth pressure in unsaturated soils

Ali Pirjalili,Ali Mirzaii,Aliakbar Golshani,P Delage,Y.-J Cui,A.-M Tang,S Ghabezloo,J.-M Pereira

doi:10.1051/e3sconf/20160905003

Ali Pirjalili, Ali Mirzaii + Show 6 more

Open Access

https://doi.org/10.1051/e3sconf/20160905003

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Abstract

Accurate measurement of lateral earth pressure coefficient, k , is a key step in any geotechnical investigation. Since conventional approaches for obtaining this value leads to high risk of uncertainty in the results, this paper introduces a new experimental approach for measuring the value of k , particularly in unsaturated soils. Details of the new instrument designed for this purpose is provided in the manuscript, which is capable of obtaining k value of unsaturated soils in a range of matrix suction or degree of saturation. Finally, some test results are presented that examine the accuracy of the novel apparatus in order to measure the coefficient of lateral earth pressure in unsaturated soils.

Highlights

Lateral earth pressure is a crucial issue, which affects obviously on many geotechnical applications analyses such as; underground structures, slope stability and retaining walls
In spite of the fact that most analysis are based on saturated soil mechanic principles, the major part of the earth land are composed of unsaturated soils
Experimental results show that the k values decreased by matrix suction increasing obviously

Summary

Introduction

Lateral earth pressure is a crucial issue, which affects obviously on many geotechnical applications analyses such as; underground structures, slope stability and retaining walls. Previous studies for evaluating of at-rest lateral earth pressures coefficient, k0, were based on this suggestion. Zhang et al (2009) have performed a series of tests to evaluate k0 in a recompacted expansive soil by a stress-path triaxial system They showed that k0 increasing by increasing in saturation degree of soil[10]. Li et al (2014) have carried out a centrifugal test on a clayey soil to examine k0 and they observed k0 increasing by saturation degree increase In this study, it proved that k0 value in unsaturated soil is less than that obtained in saturated soil.[11, 12]. Nowadays available information about the coefficient of lateral earth pressure behavior in unsaturated soils is limited to some experimental data that mainly focused on k0, at-rest condition exists scarcely in geotechnical applications. This paper introduces a suction-controlled approach by using a new device whereby k could be evaluated in at-rest state

Apparatus Feature

Material and Test procedure

Results

Conclusion