Numerical Simulation Of The Soil-Geogrid Interaction And Its Application In Engineering

So far, the geogrid has been widely applied in the reinforcement of soil, but the studies on the mechanism of geogrid farly leaves behind its application. Various methods were employed to investigate the problem and the finite element method is one of them. However, there exsit some difficulties in the simulation of the soil-geogrid interaction with FEM. Therefore, the aim of this thesis is to develop a appropriate model to simulate the soil-geogrid interaction.At first,the present computational models to deal with the reinforced soil are summarized and analysed. Then the author build a two-dimensional four-node and eight-node element to simulate the geogrid. These models can reflect the principal characters of the mechanical behaviors of geogrid. Based on the forementioned models of geogrid, the author programs the corresponding 3-D FEM program. Two simple examples were computed to verify the validity of the method and the precision of the model. Also, the result reveal the importance of the employment of nonlinear elastic model for the soil.In the thesis, Duncan-Chang model was applied to simulate the soil and the result indicate that it is successful. Furthermore, the geogrid-reinforced subgrade of a expressway was computed. The computational result show good agreement with the result of the centrifugal model test. Moreover, the computational result of the prototype subgrade indicate that the geogrid can improve the mechanical behaviors of subgrade and decrease its settlement. In the end, some unsolved problems in the model and method are discussed briefly.