关键词: 软黏土, 非共轴性, 定向剪切, 主应力轴旋转, 各向异性

Abstract: A series of undrained tests is carried out on Hangzhou soft clay with hollow cylinder apparatus. The stress paths which include shearing test under different-fixed principal stress directions for the intact soft clay and principal stress rotation for intact and remolded soft clay are designed to study the non-coaxial development behavior of soft clay as well as the influence of intermediate principal stress parameter b, initial deviatoric stress and induced anisotropy on non-coaxiality. The results show that the non-coaxiality of soft clay is similar to that of sand, but they are far from identical. The non-coaxial angle is quite small in fixed shear tests; and it is dependent on the loading directions; however, affected by the development of deviatoric stain, the non-coaxial angle is not 0° when the specimen is close to failure. Regardless of intact soft clay or remolded soft clay, the non-coaxial angle fluctuates with the increase of principal stress orientation α, of which the cycle period is 90°. The non-coaxial angle basically decreases with the increase of coefficient of intermediate principal stress b, but this effect is not quite remarkable. The deviatoric stress has certain effect on the angle of non-coaxial as well as its development trend. As to the test of remodeled soft clay, it shows that the non-coaxiality is not only entirely determined by the inherent anisotropy, the induced anisotropy also has a great impact.

Key words: soft clay, non-coaxiality, fixed shear, principal stress rotation, anisotropy