Research On Effect Of Rainfall Infiltration On Stability Of Earth-Rock Mixture Embankment

With the development of the national economy, the pace of highway construction is increasing fast. Because of the complex geological conditions in midwest China, more and more soil-rock mixture are used to be the construction material in the constructing. Rainfall is an important fact that causes the slope failure. Considering the stability of the slope in the rainfall, a large-scale artificial rainfall experiment in the field is carried out. Then the theory of saturated-unsaturated seepage and the limit equilibrium method etc are used to study the development ruler of seepage in the slope in the raining, and the effect on the stability of the slope. The main results are:1.Basic embankment characteristics of the earth-rock mixture are studied especially as the density, porosity and so on. The permeability characteristics and the shear strength of the different grading material under the different moisture are studied. This provides data for the following numerical analysis.2.The paper introduces the progress of the rainfall infiltration and the factors that affect the rainfall, such as the rainfall intensity, the permeability of the soil-rock mixture and so on. Then the concept of the saturated-unsaturated seepage is introduced and how the equation is derived.On this basis, the boundary condition in the seepage is introduced. And then the paper study how to choose the boundary condition in the rainfall, and the ruler of the calculation are described.3.A large-scale artificial rainfall experiment in the field is carried out. According to monitoring the displacement, the pore pressure in the slope, the displacement and the stability of the slope during the rainfall experiment, the paper discuss the process of the rainfall infiltration into the slope and analysis the effect on the slope by the rainfall.4.Finite element method is used to simulate the process of the rainfall.SEEP/W is used to simulate the distribution of the pore pressure and the water head,and then SLOPE/W is used to calculate the safety of the slope with fluid-solid coupling method to judge the stability of the slope. And then the effect on the seepage field by the rain time and the rainfall intensity is study, and then the stability is studied. 5.If the shear strength decreases caused by the rainfall,the development of stability is studied, and the effect on the slope by the green belt.