关键词: 主应力轴旋转, 空心圆柱扭剪仪, 四向动态加载, 应力路径

Abstract: The principal stress rotation has a significantly influence on the dynamic characteristics of soil. According to the function that GDS dynamic hollow cylinder torsional apparatus(HCA) can apply four dynamic loads, namely inner pressure, outer pressure, axial load and torque, the loading mode is put forward for three possible stress paths which are applied in practical engineering with the principal stress rotating, and three kinds of tests are conducted to confirm that the stress paths can be realized in the HCA. When the four dynamic loads meet some corresponding requirements, the following stress paths can be realized: ① When the mean principal stress p, the intermediate stress ratio b and deviatoric stress q are kept constant. ② the cyclic deviatoric stress q is applied when the mutation of α, i.e. the rotation of major principal stress relative to the vertical direction, is 90°. ③ When the cyclic deviatoric stress q is applied with the principal stress continue rotating. In addition, the first path provided theoretical foundation for experiment of simulating the stress paths under wave loading; the second path can be applied to simulate the dynamic characteristics of soils subjected to earthquake load; and the third path can be used to simulate the stress paths of soil around the pile under wind and wave loads and the stress paths under traffic loads.

Key words: principal stress rotation, hollow cylinder torsional apparatus(HCA), four-direction dynamic loads, stress path