Three-dimensional Elastic-plastic, Elastic Viscoplastic Finite Element And Boundary Element Coupling Method And Its Application In Geotechnical Engineering

In the paper, we establish the coupling numerical method of 3-D elastoplastic and elasto-viscoplastic finite element with boundary element, and comprehensively discuss some numerical problems resulted from coupling process. Combining the practice of geotechnical engineering, we make some analysis and calculation to several practical engineering problems. Following work has mainly been done.1. In the section about coupling method of finite element with boundary element and some numerical prclems, we chiefly discuss some numerical problems resulted from coupling process besides briefly introducing the general coupling method of finite eJement with boundary element. In order to raise computational efficiency and economize computer storage, we introduce the sub-structure method, present the idea of symmetrizing boundary element equation's coefficient matrix, and grant the method of treating simultaneous equations' singularity caused by use of load and boundary condition symmetry. To the problem of traction discontinuity in coupling surface, we adopt the method of complementing constitutive equation and using finite element, and successfully solve the problem. As a result, the calculation accuracy at a corner has been improved.