In order to investigate the screening efficiency of open trenches to the train-induced ground vibration, a new analytical model is proposed based on existing researches. The ground is firstly modeled as a fully saturated poroelastic half-space in the research of vibration isolation to moving trains. The trenches are obtained by placing three rectangular elastic layers with appropriate widths on the poroelastic half-space. The middle elastic layer is treated as the embankment, upon which the rails and the sleepers are placed. The sleepers and the rails are modeled as transversely isotropic Kirchhoff plate and Euler-Bernoulli beams respectively. Blot＇s theory is applied to characterize the poroelastic half-space. By Fourier transforms and Fourier series, the governing equations are solved in the transformed domain. The investigation reveals that, the screening effects of open trenches improve as the train speed increases. The effects of coupling between the soil skeleton and pore water on the screening efficiency is apparent, especially when the train speed exceeds the Rayleigh wave speed of the half-space; the screening efficiency of open trenches decreases obviously as the permeability of the ground increases. In addition, the screening efficiency of the trench on poroelastic half-space is much better than that on elastic half-space to the train-induced ground vibration for the supercritical-train-speed case.
Rock and Soil Mechanics