Study On Development Regularity And Susceptibility Of Landslide And Collapse In Lv-Liang Mountains

The terrain fluctuation of Lv-liang Mountains is large,the geological environment is complex,the human engineering activity is severe,landslide and collapse frequently happens in this area which urgently needs to make the reasonable geological disaster prevention plan,therefore there is a must to carry on geological disaster research and the susceptibility assessment in order to provide the basic data and the technology supporting for the geological environmental protection and improve the level of disaster prevention and mitigation.The development of landslide and collapse in the study area is influenced by topography and geomorphology,geological structure and meteorological and hydrological factors such as river erosion and rainfall.This thesis relies on the China Geological Survey "Urban Geological Hazards Investigation in Lv-liang Mountains " project.Taking the landslide and collapse of Lv-liang Mountains,this paper analyzes its distribution characteristics and development law,and quantifies the influence degree of each influence factor imposes on the disasters based on fractal theory.By using GIS technology,the deterministic coefficient model and AHP model(CFAHP),the deterministic coefficient model and the two-element Logistic regression analysis model(CF-LR)and the Weights Of Evidence model(WOE),these three methods were separately used to research the disaster susceptibility of Lv-liang Mountains.This paper mainly gets the following results and conclusions:(1)By collecting landslide and collapse and related environment and geological data in the research area,this paper summarizes the distribution law and development characteristics of landslide and collapse,and by analyzing its influencing factors,choose 8 factors contains elevation,slope,slope elevation,slope type,slope aspect,rock groups,river distance and precipitation as the evaluation factors of landslide and collapse susceptibility.(2)Based on fractal theory,taking the disaster distribution density in each segment of each influence factor as the index,this paper analyzes the segmented fractal dimension characteristics of disaster distribution and influencing factors,and then reveals the contribution rate of each influence factor to the development of landslide and collapse.The results shows that the disaster distribution and 8 evaluation factors showed variable dimension fractal relationship,and development of landslide and collapse is controlled by various factors.According to the cumulative and transformation orders and fractal dimension values,the contribution rate of each evaluation factor to landslide and collapse is sorted as: Elevation> Slope aspect>Precipitation>Slope elevation>River distance>Rock groups>Slope type>Slope.(3)CF-AHP method combines qualitative and quantitative method,the deterministic coefficients of each factor of landslide and collapse are obtained based on the deterministic coefficient method,and the weight of the evaluation factor is determined based on the analytic hierarchy process,the susceptibility result map is obtained from the sum of weights and the deterministic coefficients.Based on the exponential probability theory,the CF-LR method gets the influence weight of each evaluation factor by analyzing the geological environment differences of the area which contains landslide and collapse and the area which not contains through regression analysis,the susceptibility result map is obtained from the sum of weights and the deterministic coefficients.WOE model is based on conditional probability statistical function,by analyzing the contribution rate of each evidence factor to landslide and collapse,the susceptibility result map is obtained from the sum of evidence factors.(4)By using ROC curve to test the evaluation effect of the above three methods,the AUC values are 0.749,0.745 and 0.731 respectively,which shows that the three methods all have high accuracy,the CF-AHP method has the best result and divides it into five susceptibility areas contains extremely high,high,medium,low and extremely low by natural breakpoint method.