The innovation of multiple mechanism boundary surface plasticity model is that the effect of rotation of principal stress axial directions and large shear displacement of sand in the earthquake induced liquefaction are taken into account at the same time in the model 独到之处在于所建立的多机构边界面塑性模型能够同时考虑土体在复杂荷载作用下主应力轴旋转的影响和砂土地震液化时剪切大位移特性。