Stability Analysis Of A Rainfall-induced Landslide In The Area Of Ailao Mountain

Rainfall-induced landslide, which has a great relationship with the rainfall, is arepresentative one in the geological disasters. It is an effective way to study rainfalllandslides by monitoring the rainfall groundwater level and deep displacement of thelandslide area and making stability evaluation for the relevant contents.This paper takes Nanjian landslide as the object of the research in the area ofAilao Mountain. Based on the geological survey and a good analysis of geologicalenvironment conditions by combing with the abundant rainfall from the year of2008to the year of2013, groundwater level and the monitoring data of the deepdisplacement, the relationships among deep displacement of landslide, rainfall, thechange of groundwater level were investigated. And it was given a preliminaryillustration that how the landslide deformation was influenced by rainfall andgroundwater level.A simulation study was adopted for the stability and deformationtrend of landslide by means of SEEP/W software and the SLOPE/W software.Themain research conclusions are as follows:1. Combing with the rainfall of August in2013, the groundwater level and deepdisplacement field monitoring data, the studies have shown that landslide affected bycontinuous heavy rainfall, the deformation of the landslide movement is closelyrelated with rainfall and has a certain hysteresis. Deep displacement monitoring canbetter show the locations of landslide deformation, so as to determine the slip zone.2.Studied on the physical and mechanical property of landslide zone and slidingsoil by triaxial shear test, and got shearing strength parameters. Limit equilibriummethod was used to analysis the stability. By calculating the coefficient of stability inthe natural state and the water-saturated staterespectively, the studies have shown that,in the natural state, the stability coefficient were1.28, which showed a fairly goodstability; In the water-saturated state, the landslide stability factor were0.89, whichshowed a poor stability and the landslide would have a deformed movement.3. By calculating the coefficient of stability under different rainfall conditions bythe Geostudio software, the result have shown that, the continuous heavy rains increased the saturation of the landslide, reduced the shearing strength of the landslide,and reduced the stability coefficient of landslide. For250mm/d in rainfall intensity,after60hours later, the stability coefficient reduced from1.264to1.055, the landslidewas in unstable state, once the rain lasted more than66hours, the landslide wouldhave a deformed movement in the whole.