Numerical Study On Stability Of Loess Slope

Loess is widely and deep distributed in China. With the long-term soil erosion, it is shaped many ravines and a large number of loess slopes. The stability of the loess slope is poor for the loess structure is loose and large pores. The loess geographical distribution often is earthquake-prone areas in my country. With increasing construction in the loess area, under static and dynamic the stability of the loess slope concerns people’s personal safety, lives and economic development in this area. And researches about this are imperfects, so the subject of this paper is of great significance.Using the limit equilibrium method and strength reduction method analyses uniform and non-uniform loess slope of failure mode in limit state and law of uniform and non-uniform loess slope stability in different slope height, slope ratio and weak layers in different locations (only in the non-uniform loess slope) under the static. Using the pseudo static method and completely dynamic method analyses uniform and non-uniform loess slope of destruction process in limit state and law of uniform and non-uniform loess slope stability in different slope height, slope ratio and weak layers in different locations (only in the non-uniform loess slope) under the dynamic. The following conclusions:1. Under the static, the uniform loess slope is tension-shear composite damage in the limit state and the arc slip surface threads slope angle. With increased the slope height, the uniform loess slope of safety factor is decreasing and the relative difference of the calculated results of the two methods is2.8%to4.5%; with decreasing the slope ratio, the uniform loess slope of safety factor is increased and the relative difference of the calculated results of the two methods is2.6%to4.6%. The potential slip surface of the two methods is almost coincident.2. Under the dynamic, the uniform loess slope is tension-shear composite damage in the limit state and the destruction process is from slope angle and develops to the top slope. With increased the slope height, the uniform loess slope of safety factor is decreasing and the relative difference of the calculated results of the two methods is0.38%to2.1%; with decreasing the slope ratio, the uniform loess slope of safety factor is increased and the relative difference of the calculated results of the two methods is1.32%to2.79%. The potential slip surface of the two methods is not larger difference. 3. Under the static, the non-uniform loess slope is tension-shear composite damage in the limit state and the slip surface of strength reduction method is deeper the slip surface of limit equilibrium method. With increased the slope height, the non-uniform loess slope of safety factor is decreasing and the relative difference of the calculated results of the two methods is-0.69%to3%; with decreasing the slope ratio, the non-uniform loess slope of safety factor is increased and the relative difference of the calculated results of the two methods is0.95%to3.66%; With increased the weak layer depth, the non-uniform loess slope of safety factor is decreasing and the relative difference of the calculated results of the two methods is-1.54%to1.85%. The slip surface of strength reduction method is deeper the slip surface of limit equilibrium method.4. Under the dynamic, the non-uniform loess slope is tension-shear composite damage in the limit state and the destruction process is from slope angle and develops to the top slope. With increased the slope height, the non-uniform loess slope of safety factor is decreasing and the relative difference of the calculated results of the two methods is2.22%to4.76%; with decreasing the slope ratio, the non-uniform loess slope of safety factor is increased and the relative difference of the calculated results of the two methods is2.65%to6.76%; With increased the weak layer depth, the non-uniform loess slope of safety factor is decreasing and the relative difference of the calculated results of the two methods is2.42%to5.45%. The slip surface of completely dynamic is deeper the slip surface of pseudo static method.