Predicting Shear Strength of Unsaturated Soils over Wide Suction Range

Abstract

Unsaturated soils over a wide suction range are widespread in nature. The shear strength of unsaturated soils is a fundamental property in various geotechnical designs. In this paper, a systematic study was conducted to investigate the effect of soil type on the shear strength of unsaturated soils. Shear strength for different types of soil over a wide suction range can be roughly classified into three types. Numerous existing shear-strength equations of unsaturated soils were used to predict the shear strength of different types of soil over a wide suction range, and the advantages and limitations of those equations were discussed. In addition, new equations for the shear strength of unsaturated soils were proposed based on the relationship between the average skeleton stress and the suction over a wide suction range. The results showed good agreement between the predicted and measured shear strengths results over a wide suction range for sand and silty soils.