Abstract:At a large number of disaster sites, it has been found that even if the ground inclination is extremely flat (1°~5°), the ground surface may undergo long-distance lateral deformation due to earthquake loads. In order to understand the deformation characteristics of this kind of sand, the research used the concept of water inflow in an improved hollow cylindrical torsion shear tester. Subsequently, a constant shear stress static liquefaction test was used to determine the possibility of sample flow under drainage conditions and small initial static shear conditions.In order to highlight the comparison, the same sample was used for the undrained cyclic loading test to observe its behavior characteristics. The research found that:(1) The continuous flow characteristics of Toyoura sand can be observed under small initial static shear stress; (2) The continuous flow characteristics of sand are determined by the initial density, which also affects the volume expansion characteristics of sand; (3) The static liquefaction test shows that the flowing sand sample can flow under the water gushing mechanism, and even if the sample is liquefied, it shows non-flowing characteristics in a typical undrained test. This study enriches the related research on the fine sand area, and can provide a certain reference for sand liquefaction analysis.