Dynamic Response Analysis Of Non-homogeneous Elastic Foundation

With the continuous development of China’s transportation, the speed of the vehicle running faster and faster, The dynamic response of a moving load of foundation gets more attention of experts and researchers. Under this background, the research of dynamic response of soil under moving load has a very important theoretical and practical research significance on the civil engineering, railway engineering, road engineering, and other fields.This dissertation starts with an introduction of the research status of dynamic response of soil under moving load. Then, on the basis of predecessors’research, based on the elastic theory, the dynamic response of non-uniform foundation under the action of the moving load has carried on the thorough research. The main contents can be summarized as follows:1. The non-homogeneity of soil’s shear modulus changes with the depth of the foundation has a great influence on the deformation of the foundation under the action of the load. Previous research work mostly adopt the model of multi-layer foundation to study this problem. However, the formation of the foundation soil is a natural geological process of history. Generally, soil shear modulus with depth will be continuous variation. It will be more close to the engineering practice that by adopting the foundation model reflecting the characteristics of soil.2. We can use moving coordinate transformation, and combine with Fourier transform to analysis the dynamic response of layered heterogeneous foundation under moving loads. Under the comparison with other methods validation, comparatively analysis the speed of moving load, the non-uniform degree and surface soil’s shear modulus changes influence on dynamic response. Based on elastic theory, expand the loading function in the form of Fourier magnitude. Assuming the series form of the response function, and then through the methods of converting the partial differential equation into ordinary differential equation to get the answer, it is concluded that the response of each point in the soil of the inhomogeneous foundation under moving load. Then traveling through the boundary conditions and material parameters to solve and get the numerical solution of the problem, and discussed the change of the response of soil when the parameters change.3. Based on the non-homogeneous foundation of2D and3D with an elastic super stratum, dynamic response of soil under moving load is studied. Through theoretical derivation, the shear modulus which can arbitrary variation with depth, the analytical expressions of various physical quantities were obtained under moving load. Considering soil shear modulus which had power function gradient change through thickness, through the analysis of the numerical example and discussion the foundation non-uniform parameters, load moving speed and shear modulus of foundation surface, which to the influence rules of the foundation mechanical response.Finally, on the basis of the full working summary, putting forward some suggestions and prospect for the follow-up research work and methods.