Extension of three-dimensional discontinuous deformation analysis for solid block motions in predefined fluid field

Abstract

Solid–fluid numerical simulations involving open channels are usually complicated, especially for large solid displacements. An extended three–dimensional discontinuous deformation analysis (3D DDA) method incorporating depth-integrated two-dimensional fluid dynamics was proposed to evaluate solid movement considering fluid actions. In this method, two types of fluid forces on solid blocks, buoyancy and drag forces, are calculated under complex fluid surface conditions and behave as external forces on solid blocks. The accuracy of the extended 3D DDA method in calculating the block buoyancy and fluid drag forces was validated using a block acceleration model. A hypothetical open-channel model involving non-uniform and asymmetric terrain was studied to show the extended 3D DDA method is applicable to study sliding mass deposition in general cases. A hypothetical bridge unseating case threatened by flood and floating objects was then studied, which showed that both the uprising flood and floating objects could cause serious damage to a bridge in a flood event. Finally, the deposition of sliding mass in the Yangjiagou landslide was simulated, demonstrating the influence of fluid dynamics on the deposition characteristics. The results showed that the extended 3D DDA method is adaptable and efficient in analyzing discrete block systems involving open-channel fluid action.