中文摘要：

用浙江大学空心圆柱扭剪仪对杭州原状软黏土进行了固结不排水主应力轴旋转试验,试验中保持平均主应力、中主应力系数和切应力不变,进行了应力路径和各应变分量可靠性分析,并在此基础上探讨纯主应力轴旋转对各应变分量、广义切应变和切变模量的影响.研究表明：当中主应力系数等于0.5时,径向应变数值很小,可以忽略不计;轴向应变变化特征与环向应变刚好相反;在各应变分量中扭切应变占主导地位.在低切应力作用下,纯主应力轴旋转产生的应变很小;随着切应力增加,应变分量显著提高;广义切应变在高切应力下才适合选用.主应力轴旋转中切变模量呈＂勺＂形变化说明土体刚度逐渐降低.研究发现前期主应力轴旋转和高切应力作用对土体后期主应力轴旋转产生的变形有很大的影响.

英文摘要：

Undrained shear tests of principal stress rotation on Hangzhou intact soft clay, in which the average principal stress, the coefficient of intermediate principal stress and the shear stress were kept constant, were conducted by using a hollow cylinder apparatus （ZJU-HCA）. The reliability analysis of stress paths and strain components was carried out. Thereafter, based on the reliability analysis, the influences of pure principal stress rotation on different strain components and generalized shear strain as well as shear modulus were discussed. In all tests, the coefficient of intermediate principal stress was set to 0.5, and the test results show that the value of radial strain is very small so can be considered as negligible. The development of axial strain is opposed to that of the circumferential strain. The torsional shear strain is dominant when compared with other components. If low shear is stress applied, the corresponding strains in pure principal stress rotation tests are very small. The influence of shear stress reveals that the greater the shear stress, the higher the strain components will be. And the generalized shear strain is better to be considered only under high shear stress level. Shear modulus in pure principal stress rotation tests gradually reduced with a＂spoon＂ shape. It is proved that the previous principal stress rotation and the high shear stress have significant effect on the deformation of intact soft clay due to subsequent rotation of principal stress axes.