| Rainfall-induced landslide is one of the most harmful landslide types to people's lives and property safety in China.Research on the instability evolution mechanism and dynamic characteristics of rainfall-induced landslide has become a current research hotspot in the field of geological disaster research.This article takes two soil landslides that broke out at 9 a.m.on July 31 st and 3 a.m.on August 14 th in the first community of Siwan village,Longtian Township,Chengkou County,Chongqing City as the research object,research on the instability evolution mechanism and dynamic characteristics of Siwancun landslide based on multi-source data.The main research work is as follows:(1)Combining the historical disaster data and field surveys in the study area,the Siwan village landslide is located in a section with a high risk of slope instability.It is a typical area with extremely high risk of geological disaster.The natural and geological conditions of the Siwan village landslide are analyzed,and various factors affecting the formation and destruction of landslide in the landslide area are summarized.(2)Determine the basic characteristics of landslides and the instability mechanism of landslides based on regional geological data and field survey,combined with multi-source data such as Google remote sensing images,UAV aerial photography,recent precipitation data,historical landslide data in the region and field investigation data;The deterministic coefficient method(CF method)was used to quickly analyze the composite effects of topography,geological conditions,meteorology,hydrology,human activities and other factors on landslides.(3)Using GEO-STUDIO software to conduct a numerical simulation analysis of the stability evolution of the Siwan Village landslide on July 31(hereinafter referred to as 7.31 landslide)under rainfall conditions,to study the mechanism of rainfall inducing deformation and failure of the landslide,and the results show that rainfall is the main cause of landslide in Siwan Village.The transfer coefficient method is used to calculate the stability of the main engineering geological section of the accumulation body and potential slip area of the Siwan Village landslide on August 14(hereinafter referred to as the 8.14 landslide),and analyze the stability of the rock and soil mass in the landslide accumulation body and potential slip zone under different working conditions,the rock and soil mass in the accumulation body and potential slip zone may still collapse again under adverse conditions such as rainfall.(4)The discrete element numerical simulation software Mat DEM was used to simulate the failure movement process and its accumulation and distribution of the 7.31 and 8.14 landslides in Siwan Village.A numerical model of landslide was established based on the digital elevation model of the study area before and after sliding,sliding surface,soil-rock interface,bedrock surface and model base.Comparing the simulated accumulation distribution pattern with the actual disaster situation,judging the best combination of macromechanical parameters of the gravel soil in the landslide source area;according to the simulated displacement field,velocity field,Energy curve and thermal energy curve,study the failure movement process of 7.31 landslide and 8.14 landslide and their accumulation and distribution form.The simulation results of the8.14 landslide hazard area are ideal and in line with the actual situation;7.31 landslide due to the small volume of the landslide and the susceptibility to vegetation during the sliding process,the simulation results of the hazard area are different from the actual situation. |
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