Numerical Analysis On The Stability Of Slopes Under Rainfall Infiltration

Large and continuous precipitation in Southwest of China results in landslides of the natural and artificial slopes in this area in rainy season, as well as a great threat to the safety of people’s life and property. Research on stability of the slopes under rainfall infiltration has theoretical and practical significance.By taking a highway slop of Yunnan province as the research object, on the basis of the field survey and laboratory test of general geological characteristic of this area, using finite difference software FLAC2D establishes a numerical model of the slope. Analysis the stability of the slope under different rainfall intensity, durations and patterns, and studies on the reinforcement effect of anchor on the slope under different rainfall patterns. The results show that:Rainfall infiltration leads to a significant increase in saturation degree of the slope when the rainfall intensity is relatively large. The rainfall is much easier to infiltrate into inside of the slope when the rainfall intensity is relatively small. At the same rainfall duration, shear strain increment and plastic zone increase with the increase of rainfall intensity. The slope demonstrates a tension failure and a shear failure under rainfall infiltration. The damaged surface gradually extends to the top of the slope from the interface of rock and soil layers under rainfall infiltration. The displacement of the slope is large under intensive rainfall. The horizontal displacement of the slope increases with the decrease of elevation, while the vertical displacement of the slop decreases with the decrease of elevation. And the displacement of the slope increases with increment of rainfall duration, while the factor of safety of the slope decreases with the increase of rainfall duration.The saturation region of the first level slope is the largest when the rainfall intensity increases, followed with the uniform rainfall intensity and rainfall intensity decreased under different rainfall patterns. The displacement of the slope is the largest when the rainfall intensity decreases at the same elevation before the slope is supported with bolts, respectively following with the uniform rainfall intensity and decreased rainfall intensity. There is a significant increase in the factor of safety of the slope and decrease in the displacement of the slope after the slope supported with bolts. Compared with the displacement before the slope is supported with bolts, the supported slope has less displacement under the different rainfall patterns.Rainfall infiltration causes an increase in axial force and shear force of the bolts. Axial force and shear force of the bolts are similar under rainfall infiltration with different rainfall patterns.