Adaptive Mesh Refinement and Error Estimate for 3-D Seismic Analysis of Liquefiable Soil Considering Large Deformation

Abstract

Such soil structures as river dikes, high way embankments and earth dams frequently have been damaged during major earth- quakes, often due to liquefaction of embankments and foundation soils. In most cases, unacceptable, large, permanent deformation has occurred due to liquefaction of the supporting, loose, cohesion- less foundation soil. The seismic design of soil structures in these liquefiable soils poses very difficult problems for analysis and design. The possibility of liquefaction necessitates further investi- gation not only experimentally but by numerical analysis. ABSTRACT The focus of this paper is on 3-D adaptive analysis method of liquefiable soil improvement of the approximate quality of nonlinear numerical simulation of the liquefaction process with large deformation. This adaptive tech- nique was applied to the 3-D non-linear FE analysis of liquefiable soil considering large deformation, including the liquefaction phenomenon. The cyclic elasto-plastic model and updated Lagrangian formulation were adopted in the three-dimensional FE analysis. The fission procedure belonging to the h-refinement indicated by the error estimator, a posteriori error estimate procedure depending on L 2 -norm of strain and superconvergent patch recov- ery method, was used. The convergence of this error estimate scheme and the effectiveness of h-adaptive mesh refinement were shown by simple examples. The adaptive FE method was applied to the three-dimensional prac- tical seismic analysis of an embankment constructed on liquefiable soil, and its efficacy demonstrated in detail. Application of the adaptive technique to the nonlinear analysis of saturated soil, including the liquefaction process, is a valuable step in the three-dimensional seismic analysis of liquefaction.