Analysis of Influencing Factors on Stress Path in Soil Element of Ground under Moving Load

In order to study the stress path in soil element of ground under moving train load and the influence of moving speed, depth and the initial stress state of soil element on the stress path, the steady-state solution of stresses in ground were obtained based on the model of Euler beam on elastic half space under one moving load. The stress path in soil element under the load moving line was analyzed. It is found that the stress state changes from pure shear to triaxial shear and back to pure shear finally in one cycle. According to the stress path curves for different moving speeds, it is found that when the moving load is high, the maximum deviator stress decreases, but the horizontal shear stress increases dramatically. The stress path curves in soil element at different depth for both a low speed and a high speed (near to the Rayleigh wave speed) were presented. It is shown that horizontal shear stress and deviator stress increase first with the depth's increasing and decreases after reaching the maximum value. The shape of stress path curves at different depth is close for a low speed but differs greatly for a high speed and the soil element at shallow depth is mainly in a tensile state. The stress paths for different initial stress states were also presented. And it is found that the initial stress state influents stress path greatly. The bigger the initial deviator stress is, the more unobvious the variation of stress state and the principal stress axes rotation are.