A VALIDATION FOR SOIL SCOURING SIMULATION BASED ON AN ISPH-DEM COUPLING METHOD

Abstract

The mechanisms of the seawall destruction have been studied and the following three causes have been investigated in general; 1) horizontal force due to the water level difference, 2) soil scour and erosion behind the seawall during overflow, 3) seepage failure associated with the reduction of the bearing capacity. Whereas, the collapse predictions by complex destruction factors have not ever been realized.

Hence, to predict various destruction due to interaction between water and soil, a multiphase flow simulator utilizing the Incompressible Smoothed Particle Hydrodynamics method (ISPH method) for water and Discrete Element method (DEM) for soil is developed in our research group. In this research, we simulated scouring phenomena due to vertical jet experiment for a validation test. In our SPH model, a turbulence model is adopted, and the velocity in the vicinity of the gravel DEM particles may decrease because of the eddy viscosity effect of the turbulent model. Then, we propose a modification to take into account the influence of unresolved turbulent flow. The modified drag force model shows a better performance to represent the gravel movement during this vertical jet simulation. Consequently, the result in this research indicate possibility that the gravel movement force needs to be supplemented energy.