| The urban rail transit and high speed railway have developed rapidly in recent years, and the environmental vibration caused by them gets many experts and research schloars’attention. According to the current studies, the soil vibration magnitudes induced by moving trains are so small that it is possible to treat the soil as elastic body in the aspect of solving the soil vibration problems. The elastic semi-infinite space’s numerical model has been created in the paper with the dynamic and static features researched.Firstly, the numerical modal with a controllable parameter is created using mapping infinite elements and finite elements. The shape fuction which is suitable for making the explicit expressions of element stiffness matrix is proposed. Compared with the theoretical solutions in point load, the stiffness ratio coefficient suiting for the inside finite elements is got which can be used to get the concerned semi-infinte space’s numerical results in complex load and it also can be used to proved the simulations’ precision. Compared with the finite element model’s numerical solutions, the simulations’high efficiency and precision are proved.Secondly, using the decay infinite elements and finite elements the elstic2-D infinte area numerical simulation is proposed to research the dynamic characteristics. Base on the engineering back ground of trains moving on tracks, a2-D elstic infinite space dynamic model is proposed with plane starin elements. The stiffness matrix and mass matrix of the decay elements are proposed without considering the wave number. It has changed the amplitude attenuation coefficient. The elastic semi-infinite space’s dynamic characteristics are researched under harmonic load, and the effectiveness about using the decay infinite is got throught the compare between the coupling model solution and the finite model solution, which lay a solid foundation for the three-dimensional model and train load’s accurate simulation. |
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