Model Tests For Resurrection Mechanism Of Ancient Landslide Induced By Rainfall And Slope Cutting

With the continuous development of various types of engineering construction in southwestern mountainous areas,landslide disasters occur frequently due to the topography,and landform.Among the disasters,there are many incidents of the resurrection of ancient landslides.The resurrection of ancient landslides is a complex process in which the slope gradually develops from a stable state to an unstable one.So far,people are not very clear about the resurrection mechanism of the ancient landslides induced by cutting slopes and rainfall.Therefore,relying on the National Science and Technology Support Project(No.2015BAK09B01),this paper is based on the ancient landslide project in “Lijiawan”,through physical model test,and study on resurrection mechanism of the ancient landslide induced by cutting slopes and rainfall.The main research work and conclusions are as followed:(1)In order to carry out the physical model test,it should be combined with a prototype project to study the mix ratio of similar materials and establish a test model.Based on the similar theory and the prototype of the ancient landslide in Lijiawan,the model test device and test plan were designed;the similar materials in the model test were matched by the compressive strength characteristics test and shear strength characterist ics test.Test and use of orthogonal test principle to analyze the sensitivity of various composition materials,and to obtain the best mix ratio of similar materials for rock mass and weak sandwich;to arrange monitoring points and establish corresponding edges according to the designed test plan.Slope test model.(2)The study on the landslide model tests of the Lijiawan landslide in the east and west landslides was conducted under cutting slopes and different rainfall.The displacement and stress distribution of the slope model under the cutting slope action and the displacement of the slope model under rainfall were analyzed and the change of water content.The results show that the slope model produces small displacement during the cutting slope process and redistributes the stress.The stress concentration phenomenon occurs at the foot of the cut slope.In the rainfall process,the model shows the same trend of change in water content according to different rainfall.However,landslide deformatio n experiences different stages and the final deformation is different.(3)Based on the test results of physical model,the author analyzes and summar izes the resurrection mechanism of the ancient landslide in Lijiawan.Through the combinat io n of the test results of physical model and engineering prototypes,the resurrection mechanism of "Lijiawan" landslide(East and West landslides)induced by cutting slopes and rainfall is further analyzed;the main reason is that the slope process produces high stress areas at the foot of the slope.Moreover,in the course of rainfall,rainwater infiltration weakens the weak interlayer,and makes the landslide greater than the antisliding force.Therefore,the landslide cuts along the weak interlayer at the cutting slope,causes the slope of the landslide area to appear tensile fractures,and finally induced the "Lijiawan" ancient landslide(East and West landslides)to revive.