Research On The Influence Factors Of Saturated-Unsaturated Seepage And Its Effect On Slope Stability

Disaster of embanks often happen under flood and rainfalls. In order to analyze the influences of water level variation and rainfall on the distribution of seepage and embankment's stability, in this paper, the change of seepage field under the condition of different water level or rainfall is studied based on the saturated-unsaturated seepage theory. And the safety factor of embankment's stability is calculated based on the theory of unsatutated-soil shear stress to search for the action of various factors. The following is included :1. Explaining the fundamentals of the steady-unsteady saturated seepage and its initial and boundary conditions. Further, clarify the motion and differential equation of unsaturated seepage. Taking account of the inhomogeneity permeability coefficient of the soil, the seepage state of the unsaturated soil is classified as three types. Governing equation is finally gained.2. Comparing with three solution methods of the seepage. Thinking of the characteristic of solving saturated-unsaturated transient seepage field, the FEM format of differential equation is deduced based on Galerkin method of weighted residual. The classical counting model is compared with measured value to verify the feasibility of SEEP program. The reasons of different results are analysed based on the two seepage theory.3. The seepage parameter of clay soil and sandy soil is fitted by orogin7.0 numerical handling program and the best is chosen. Deducing the calculation method of shear strength of unsaturated soil, the applied equation is searched , from which the formula of safety factor of embankment's stability is derived.4. Analyzing the change of saturated-unsaturated seepage field for embankment, bank slope and foundation ditch, the distribution of pore water pressure is calculated and introduced into the formula of safety factor to find the law under different condition.In this paper, the influences of main factor on the seepage field and stability are discussed, which offer decisions for appropriate design of embankment, effective protection and forecast of landslide.