Spatial Prediction Of Cretaceous Gravel Rock Collapse In Dianjun Area Of Yichang City

Yichang Dianjun Area is located in the transition zone from the mountainous area to plain.Sand breathe is mainly developed in the area.The rock formation inclination is slow to the level,which is prone to the collapse disaster of slow dip bristle body with very typical characteristics.In view of this,based on the basis of detailed statistics of existing conglomerate collapse disasters in Yichang Point Military Area Command,this paper summarizes the distribution law of the collapse,reveals the damage mechanism,and establishes a spatial prediction and evaluation index system through the relationship between damage mode and control factors,and finally conducts spatial prediction and evaluation with GIS.The main research contents and conclusions are as following:(1)Study on the damage mode of dangerous rock collapse disasterThere are 22 typical conglomerate collapse disaster sites in the study area.We determine the damage pattern and control factors through analyzing the distribution law,the destructive pattern and the damage mechanism.The results show that the distribution density of dangerous rock collapse disaster in the study area decreases from east to west;the dangerous rock collapse failure mode is mainly dumping type,followed by sliding type and filing type.Sand conglomerate damage often occurs within 123?243m.When rock joints and fissure density is large,and more prone to dumping damage under the slope inclination of 10?22.The possibility of three damage within the slope range of 7?19.(2)Establishment of index system and analysis of single-factor correlationThe influence factor index system of dangerous rock collapse disaster was established according to the control factors of dangerous rock collapse,draw the special map of influencing factors and analyze the correlation between the disaster distribution and influencing factors.The results show that the index system includes slope,slope,slope height,road distance,bedding inclination,vegetation cover type,rock formation,joint gap,and the correlation coefficient of dangerous rock collapse disaster and its influencing factors are less than 0.5,meeting the requirements of spatial prediction and evaluation.(3)Spatial prediction of dangerous rock collapse disaster in the study areaBased on the weight of the GIS spatial superposition method,the study zoning is divided into four levels: A),high prone zone(B),medium prone zone(C)and low prone zone(D).The results show that extremely high prone area accounts for 1.08% of the study area;high prone area is 47.20% of the study area;medium prone area is 51.67% of the study area;low prone area accounts for 0.05% of the study area.Comparing the research results with the disaster point distribution results of actual site investigation of 95.46%.The main innovation of this paper is:1.The failure mode of dangerous rock collapse in the area is mainly dumping type,followed by sliding type and filling type.Falling damage often occurs within 123?243m.When the joint crack density of rock stratum is large,the collapse body is more prone to dumping and it is more prone to dumping damage under the bedding slope angle of 10?22,with the possibility of three damages within the slope range of 7?19.2.Computing the superposition weight value of influence factor layer by PSO-RF method,it improves the accuracy of spatial prediction system and reduces the error in random forest method.