Simulation of Cyclic Direct Simple Shear Loading Response of Soils Using Discrete Element Modeling

The Direct Simple Shear (DSS) test is one of the laboratory element testing devices that has been widely used to assess soil behavior. Although the DSS test is considered to simulate the cyclic shear loading mode from the earthquakes in an effective manner, the most commonly used versions of the test device (such as the NGI-type DSS device) do not provide means of measuring the lateral stresses on the specimen. This, in turn, results in an inability to define the complete stress state during DSS testing. In recognition of this, along with the need to model soil behavior, numerical modeling of the laboratory element DSS testing process was undertaken using a discrete element method (DEM). The research work presented in this paper indicates that DEM simulations can effectively capture the cyclic shear behavior, including excess pore water pressure generation, observed in laboratory constant volume DSS testing of sands.