The Steady Of Xiakou Landslide Under The Different Rainfall Conditions

Landslide is a common natural disaster, caused by many factors. Rainfall is the most common of which the most important one. However, more than 60% of slope instability is caused by rainfall. The rain-induced landslide mechanism and the corresponding method of evaluation is always academics, engineering concern, and difficult to resolve an issue. However, at present there is no available geotechnical engineering research results. Therefore, this study is of great theoretical significance and engineering significance.In this paper, the following main research results are made.(1) Against rain-induced landslide mechanism and the corresponding methods for the evaluation system of research. Initial set up a "scene from the deformation monitoring and analysis→indoor physical and mechanical tests→model Mechanism→rainfall seepage slope Numerical simulation→rainfall induced slope instability evaluation, "the system. In combination with Ya'an Xiakou landslide, using the above method for system analysis.(2) Identify Xiakou landslide in a basic geologic and hydrological conditions on the basis of in-depth analysis of the Gap landslide engineering geological characteristics and deformation characteristics, thereby undermining its mechanism of analysis. Gap landslide through precipitation, surface displacement, displacement and deep groundwater level in more than two years of on-site monitoring data analysis, Landslide found that the deformation of the size and number of rainfall in a very good relationship. Slope displacement apparent seasonal variations and in the rainy season, the slope deformation and entered the dry season, the displacement slowed down, become more stable. The analysis also found that the slope in front of larger displacement, the central and rear China slowdown, and the external rear alleviate some more.(3) Establish an expression for landslide critical value of rainfall induced area and probability rainfall influences landslide on basis of logic regression model. Make a quantitative survey on expression for rainfall critical value of induced area on basis of logic regression coefficient. Establish an expression for rainfall critical value with consideration of rainfall intensity and process by statistic analysis of landslide, rainfall and rainfall process. Study indicates that landslide in rainy urban area is related with rainfall within the latest 4 days, namely, rainfall on that day, rainfall on the day before, rainfall of two days ago and rainfall of three days ago, among which 1st day rainfall makes fundamental impact on landslide. Rainfall critical value is determined to be the amount of rainfall on four days. Expression for landslide critical value of rainfall induced area in rainy urban area:Landslide in rainy urban area is closely related with rainfall on that day and that on the latest three days. After calculation by SPSS, an expression for probability of landslide related to four days' rainfall is obtained as follows:(4) By the software of Visual-Modflow, which is based on definite difference theory, numerical modeling has been taken for saturated and unsaturated seepage field at Xiakou landslide on different rainy conditions. The result shows regularity for change of groundwater level at landslide site after the rain saturates the ground.(5) The result shows the effect that intensive parameter reduction along with the water content increase is very notable, by the shearing test for landslide aspect and slippery belt silty clay under the different containing water states, But the soaking effect of water is not equally complete to the different type soil aspects. The thick crushed stone soil reaction is weaker, but the thin soil reacts clearer.(6) Calculating formula for saturation line of groundwater at slope when rainfall and water level rises or descends is reasoned by converting forward and backward Laplace on certain assumption. For convenient application, this formula is simplified by merging of polynomial.(7) Make discussion on mechanism of landslide on slope induced by rainfall, as well as evaluation of stability of the slope. According to this, analysis and evaluation has been made on the stability of Xiakou landslide on varied rainfall conditions.