Tri-axial shear strength of Shanghai unsaturated soft clay

The mechanical properties of unsaturated soil are quite different from those of saturated soil because of the influence of suction.Results obtained with the strength theory of saturated soil could not be directly applied to solve the problems related to the unsaturated soil.Some tri-axial tests were carried out herein to analyze unsaturated soil strength for Shanghai soft clay.It was shown that,with low suction,the tri-axial strength for unsaturated Shanghai soft clay was directly proportional to suction.These results certified the applicability of double-variables strength theory for unsaturated soil.The tri-axial shear coefficient ?b for Shanghai soft clay(④)is 10.6°.With the development of unsaturated soil mechanics,researches on the application of unsaturated theory for solving geotechnical engineering problems in Shanghai area should be strengthened.