Analysis On The Behavior Of Tailings-dam Subjected To Rainfall Inflitration

The response of unsaturated soil under rainfall infiltration is an important part of geotechnical studies. The decline of the suction resulted by rainfall in non-saturated soil reduce the shear strength of slope and dam, and cause their stability lower. Therefore, the analysis of the response of various non-saturated soil structures under rainfall is very necessary.Tailings dam is an important production facility. There is a large number of tailings sand and water in dams. If tailings dam once breaks, it would cause immeasurable losses in the production, peoples'lives and property. The factors affecting the stability of tailings dam are multitudinous, and the rainfall infiltration is one of the important factors. The study has some value of scientific research and application.Firstly, this paper uses the artificial rainfall field tests to study the main factor affecting the shear strength of unsaturated soils, the variation of suction under rainfall. During artificial rainfall experiment, using different rainfall intensity, contrasting different site classification (with and without vegetation), the changes of suction and the development of runoff is recorded. Based on field test data, it found that, infiltration characteristics unsaturated soil in tailings dam is basically the same as that of general non-saturated slope. Also, the essence is the change of the infiltration rate. The initial distribution of suction is affected by the solar radiation reducing along the depth. Tailings dam needs some initial reaction time. There is rapid reaction and big variations of suction in the shallow, and it gets the stable value early. As rainfall intensity is larger, soil suction reacts more rapidly, the depth impacted is greater. Influence of vegetation on tailings is that the vegetation reduces the role of impact of raindrop. Vegetation is favorable for infiltration, and infiltration depth increases, reaction time of suction is earlier than that without vegetation.Secondly, to verify the field test, and probe into the mechanism of rainfall infiltration of tailings dam, the commercial software GEO-SLOPE is used to simulate the physical model tests. It studies rainfall infiltration characteristics of tailings dam without vegetation, and it study preliminary rainfall infiltration characteristics of tailings dam with vegetation. At last, it will select some rainfall characteristics and hydro geological factors to study; it is found that, the basic rule of changes of negative pore pressure in numerical simulation is the same as that in field test, the role of the vegetation on the tailings dam is very complex. Rainfall intensity, rainfall duration, storm type and surface permeability of the tailings dam is significantly for its stability, the anisotropy of permeability is particularly significant.