Effect of Suction on Mechanical Behaviour of Unsaturated Soil: A Review

Author Name(s): Pratish P. Junghare, Dr. A.A. Mehta, Dr.P.P.Dahale, Dr. P. D. Hiwase
Author Email: jungharepratish@gmail.com

Abstract

This study reviews the mechanical behaviour of unsaturated soil under various Geotechnical problems like bearing capacity failures and the slope stability failures. To obtain a rational solution for any Geotechnical problems, field tests & numerical modelling were performed. Moreover various empirical equations and new innovating methods used to obtained desire parameters required for unambiguous analytical as well numerical modelling related to unsaturated soil were also discussed. Also, a detailed review on effect of influencing parameters on mechanical behaviour of unsaturated soil is done.

Introduction

Now a days significant change in climatic conditions were observed mostly due to Global warming. Many countries experienced either longer rainfall or higher rainfall for shorter time period as rainfall is most frequent triggering factor for slope failure in different parts of world. Moreover the rainwater infiltration and variation in ground water are predominant factor which affected by soil properties. These change in soil pressure responsible for the distinct mechanical behaviour of unsaturated soil under different Geotechnical problems. So the understanding of the mechanical behaviour of unsaturated soil and related parameters which affect the overall behaviour of unsaturated soil is very important. Slope failures in residual soils may occur due to several factors, such as weathering processes, geological activities, human interference, hydrological effect, topographical features, vegetation and climatic conditions. Infiltration of rainwater into soil changes the state of soil from unsaturated to saturated soil. It is well know that negative pore-water pressure which occurs in unsaturated soil increase the shear strength of soil. As soil will gets saturated, Soil suction decreases which finally results in decrease in shear strength. (Fredlund1993)[1]. Fig. 1 represents slope stability failure due to infiltration.

Conclusion

As above stated parameters adversely affects the slope failures and bearing capacity failures of unsaturated soil, an engineer should have a keen knowledge about all these parameters. To fulfil these requirements new innovative methods studied by previous researchers were reviewed to obtained sustainable solution of related geotechnical problems.

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