Study of effects of surface seepage parallel to horizontal surface on stability of borrowed soil in ecological slope

Supposing that the failure mode of borrowed soil with surface seepage parallel to horizontal surface is a translational sliding surface parallel to the original sloped surface along the upper surface of plane nets. Based on this failure model, the stability analysis of the soil is carried out; and then a general equation on stability thickness of the soil under earthquake and surface seepage parallel to horizontal surface is given. Stability charts for the soil are obtained after discussion on parameters of the equation. Using the charts with surface seepage parallel to horizontal surface and with surface seepage parallel to sloped surface, the stability of the soil is compared. The result shows the stability of the soil with surface seepage parallel to horizontal surface is remarkably reduced than that with surface seepage parallel to sloped surface, and reduced degree is inversely proportional to instability thickness of the soil.