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.