Numerical Analysis And Study Of Performance Of Geogrids-Reinforced Earth Retaining Walls By FEM

The study of performance behavior of geogrids-reinforced earth retaining walls is an important and practical problem In practice of geotechnical engineering. At the present time, the application and study of ge ogrids-reinforced earth retaining walls mainly deals with several problems, such as strength(the mechanism of reinforcement), stability(the analysis based on limited-balance methods), deformation(the analysis of lateral deformation of wall face), the effect of reinforcing and so on. These problems are not well settled in practice.Numerical analysis of FEM which is used to simulate the mechanism of geogrids-reinforced earth retaining walls is based on the mechanism of reinforcement, and makes up the deficiency of limited-balance methods to get the actual strain and stress of geogrids and deformation of construction. So it is closely related to the above several problems.Based on the studies of predecessors, the author makes a comparatively general study about geogrids-reinforced retaining walls. The reinforcing mechanism of geogrids which belongs to the problem of strength is discussed particularly. Base on the parameters obtained by model analysis of lateral dsformation of wall faces, the author combines with the performance and mechanism of reinforced earth retaining walls to select a series of relevant parameters which are likely to affect the performance behavior of geogrids-reinforced earth retaining walls. The two studies provide some gist for the numerical analysis and the analysis of sensitivity of parameters.Then a numerical nonlinear analysis model based on finite element method considering the filling of layers by layers and loading step by step is developed for the geogrids-reinforced earth retaining walls, which is based on the E-B mode of Duncan-Chang model of soils and the Goodman model of interfaces. Two cases studies for a large-scale test wall reinforced by geogrids and an actual geogrids-reinforced earth retaining wall on dam are made to verify the reliability of the proposed numerical method, and some credible conclusions about the computation of the lateral deformation of wall faces and the strain and stress of geogrids are obtained, which is a good test for the following numerical analysis of sensitivity of parameters.Further more, a comparative study is conducted for a varied range of relevant parameters involved in the analysis such as deformation and strength properties of backfills and rigidity, length and vertical space of geogrids, the elastic modular of wall face. Based on the computed results, the effects of these factors on distribution and variation modes of stresses anddefonnations of the system are examined and performance behavior of geogrids-reinforced earth retaining walls is discussed, some regular conclusions which are benefic to the actual engineering are summed up. At the same time, the application of FEM is developed.After above works, the author puts forward some questions required solved and expectations about the FEM of geogrids-reinforced earth retaining walls.In summary, many works of this paper are with some actual meanings. The FEM analysis and the analysis of sensitivity of parameters are significant for the design of reinforced earth retaining walls.