Numerical Nonlinear Analysis On Stresses And Deformations By FEM And Study Of Performance Of Geogrids-Reinforced Earth Retaining Walls

The performance of geogrids-reinforced earth retaining walls is one of the most important and practical issues in geotechnical engineering. However, many technical problems remain to be not well understood reasonably. Therefore this thesis tends to conduct investigation on these problems.First, the past investigations on engineering performance of geogrid-reinforced earth retaining walls are analyzed and summarized. On the basis of these analyses, a nonlinear FEM procedure for numerically analyzing the stresses and deformations of geogrid-reinforced earth retaining walls are developed and a computer program is worked out. In the proposed method, elasto-perfect plastic constitutive model based on Mohr-Coulomb yield criterion and Drucker-Prager plastic potential function is employed for soils while Goodman's joint element model is used for simulating the contact behaviour of interfaces between geogrids and soils. The computer program is validated through example analysis. Effects of the related parameters on the performance of geogrid-reinforced earth retaining walls are examined through parameter sensitivity analysis. Then the pullout forces mobilized by geogrids during loading are estimated by the present numerical analysis and other existing different methods and then compared. Based on the computed pullout forces, an empirical formula is given for defining the vertical space of geogrids. A simplified procedure for evaluating maximum lateral displacement is presented.The computed results and conclusions are instructive for engineering design of geogrid-reinforced earth retaining walls.