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| VARIATION OF THE SHEAR STRENGTH OF XIAMEN UNSATURATED RESIDUAL SOILS WITH WATER CONTENT |
| CHEN Dongxia1，2，GONG Xiaonan2，MA Kang1 |
(1. School of Architecture and Civil Engineering，Xiamen University，Xiamen，Fujian 361005，China；2. Research Center of
Coastal and Urban Geotechnical Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China) |
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Abstract Shear strength of unsaturated sandy and clay residual soils were conducted by consolidated-drained shearing method using the conventional strain controlled direct shear apparatus. Results show that the shear strength of two kinds of residual soils decreases with increase of water content. The initial water content has effect on both cohesion and frictional angle of sandy clayey soils. The relationships between cohesion，frictional angle and water content of sandy clayey soils are quadratic and power respectively. While the initial water content has negligible effect on friction angle of clay. The considerable influence of increasing water content on shear strength of residual clay is decreasing the cohesion. The variation of cohesion with water content can be described by an exponential relationship. On the basis of variation of shear strength indexes with water content，two new strength formulas of unsaturated sandy clayey and clay were established without suction component and were demonstrated by further tests. Comparisons of the calculated and measured shear strength show that the accuracy of the prediction is higher under high vertical stress. Two strength formulas can provide the good estimation of shear strength of unsaturated residual soils in Xiamen for engineering application.
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2015, Vol. 34 
