中文摘要：

在已有空心圆柱扭剪仪上开发新的控制模块,实现应力主轴以任意初始方向角开始并以任意角度幅值进行往返旋转。在此基础上,对丰浦砂开展系列应力主轴往返旋转试验。试验结果表明：1应力主轴往返旋转角度幅值和初始主应力方向角均对砂土变形有不可忽视的影响;2不同于应力主轴连续循环旋转的情形,应力主轴往返旋转时砂土由于＂楔入效应＂可能出现体胀。

英文摘要：

This paper develops a new control module for a hollow cylinder apparatus （HCA）, which allows principal stress to rotate back-and-forth at any angle. A series of experiments on Toyoura sand are conducted. The results indicate that the effects of both the amplitude of the rotation angle and the initial direction of the principle stress on the deformation of sand should not be ignored. Furthermore, sand may expand when principal stress rotates back-and-forth due to the ＂wedging effect＂. However, this will not happen when principal stress rotates continuously.