Slope Stability Analysis Of Unsaturated Soil Downstream Yellow River Levee

The research of unsaturated soil slope stability is still in exploration. Based on the test of the matric suction of unsaturated soil, the direct test of seepage of unsaturated soil and the consolidated un-drained shear test, a serial of studies are made of the variation of the seepage and the stability in the unsaturated soil slope of Yellow River levee under the circumstance of the rain, the flood, and the cooperated effect of the rain and the flood. The following will be done in this paper.1,All the tests of unsaturated soil are done in the laboratory. The samples are got from the Yellow River levee and the soil is silty clay. In order to model the true work condition, the maximum densities of the soil are the same as those in the Yellow River levee. The tests are done in turn.2,The triaxial test instrument for unsaturated soils controlled by stress and strain was used to measure the matric suction and volumetric water content of unsaturated soils; And a set of soil-water characteristic curves of silty clay were obtained. The equation of soil-water characteristic curve was also gained by use of nonlinear curve fitting. The concrete form of the Mualem equation was deduced based on the relation between the soil-water characteristic curve equation and the permeability function equation. The results calculated by the concrete form of this Mualem equation are consistent with those measured by the direct method. The concrete form of the Mualem equation was further proved to be reasonable and it provide precondition for the seepage analysis of unsaturated soil also.3,From the consolidated un-drained shear test of unsaturated soils, we get the parameters of the unsaturated soils which can be used in the slope stability analysis of unsaturated soil. The results of the test indicate that matric suction is important to the strength of the unsaturated soil.4,A serial of studies is made of the variation of the seepage and the stability in the unsaturated soil slope of Yellow River levee under the circumstance of the rain, the flood, and the cooperated effect of the rain and the flood. We get the incidence of unsaturated soils which is determined by the rain, the flood, and the cooperated effect of the rain and the flood. The incidence which is very important to the stability analysis of unsaturated soil slope varies from 1m to 2m.5,In this paper, the influence of the matric suction is also studied which increases the numerical value of the factor of the unsaturated soil slope. And it can be a help to explain the affection of the water to the strength of the soil in definite quantity.