Study On Theoretical Method For Soil Vibrations Based On TLM-PML And Vibration Characteristics Induced By Moving Loads

In recent years, the environmental vibration induced by traffic is increasingly prominent and has been paid more and more attention. Therefore, it is particularly important to effectively predict the environment vibration and its transfer laws. This paper uses the thin layer method (TLM) with boundary modeled by perfectly matched layer (PML) and sets up the vibration model of subsoil under loading. The vibration characteristics of subsoil under moving loads are calculated and analyzed, and both the transfer laws of subsoil vibration under moving load and the influential factors are systematically studied. The main comments include:(1) The basic principle of thin layer method (TLM) is introduced and furthermore the 2.5D fundamental solution,3D fundamental solution of subsoil under a point load, and 3D fundamental solution under a rectangular load are deduced. And then the energy dissipation principle of perfectly matched layer (PML) is expounded, and PML is applied into the TLM model in solving subsoil vibrations. Also, the homogeneous full-space subsoil model is taken as example, and the calculated results are compared with an existing analytical solution. The results show that the TLM-PML method adopted in this paper is reasonable and effective and can be used to solve the subsoil vibration under different types of loading.(2) The analytical formula of vibration of subsoil under moving load is derived. The influence of the speed of moving load (including sub-critical speed, critical speed, and super-critical speed) on subsoil vibrations is discussed, and the effect of parameters of subsoil on vibrations of both elastic half space and layered elastic half space is also analyzed.(3) The further study of the propagation laws of subsoil vibrations along the horizontal direction and along the depth direction is given, under the moving point load, the moving load series, and the rectangular load, respectively. Moreover, the influence of the shear wave velocity ratio and the thickness of subsoil, the speed and vibration frequency of moving loads on the transfer laws is explored.The achievements obtained from this paper have important theoretical significance and can provide the reference in assessing environmental vibrations induced by traffic.