Research On Rainfall Infiltration Characteristics And Stability Of Mounded Landslides In Southern Shaanxi

The Qinba mountains in southern Shaanxi tend to have a special internal climate and complex and diverse geological conditions,and a large number of mounded layer landslides are distributed,while the surface mounded layer landslides have a loose structure and are highly susceptible to deformation and damage under the action of high-intensity rainfall during the annual flood season,which seriously threatens the life and property safety of residents.This paper takes Hanzhong city in southern Shaanxi Province as the research area,analyzes the influence and induced role of rainfall in the occurrence and development of mounded-layer landslides,and studies the deformation development characteristics of rainfall-type mounded-layer landslides with the method of disaster statistical classification.The paper optimizes the Green-Ampt infiltration model by theoretical derivation and investigates the influence of rainfall type on the stability of mounded landslides by numerical simulation.Taking Chenjiatai landslide as an example,this paper analyzes the relationship between water content and soil shear strength based on indoor tests,and finally analyzes the infiltration mechanism and stability of rainfall type mounded landslide through numerical simulation and monitoring data analysis considering the effects of rainfall and evaporation.The main research results and conclusions are as follows:(1)The thesis collected data on environmental and geological conditions,deformation and damage,and synchronous rainfall of about 150 mounded landslides in Hanzhong City,analyzed the internal causes of landslides and main triggering factors(rainfall),summarized the distribution characteristics of regional mounded landslides in terms of scale,slope morphology,rainfall type and damage characteristics by using disaster statistics,focused on analyzing the correlation between rainfall and landslide activity,and proposed a classification method of landslides based on rainfall The classification method of landslides based on rainfall induced characteristics is proposed.(2)Based on the relationship between rainfall intensity and soil permeability,the rainfall conditions of landslides in the region are classified into three categories,and the distribution law of initial water content inside the landslide body is also considered,and the infiltration model of landslides under these three rainfall conditions is improved on the basis of the Green-Ampt model,and the modified model is verified by numerical simulation.(3)The rainfall in Hanzhong city is divided into five categories,and a generalized model of landslide on the mounding layer is established by numerical simulation.The infiltration pattern and stability change process of landslide under different rainfall types are analyzed,and the reliability of landslide is analyzed by Monte Carlo method in order to consider the change of soil parameters in the process of rainfall infiltration.(4)Taking the Chenjiatai landslide as the engineering background,numerical simulation is carried out combining field monitoring data and experimental data to explore the deformation response law of rainfall-type mounded landslide under the rainfall-evaporation effect and analyze the infiltration process of mounded landslide.