Risk Assessment Of Geological Hazards Of Important Structures On Dusi Railway

The Dusi Railway starts from Dujiangyan City on the northwestern side of the Chengdu Plain and crosses the southwestern section of the Longmenshan Fault Zone and the trapezoidal transition zone on the eastern margin of the Tibetan Plateau.The valley is dominated by geological hazards.The proposed Dusi Railway will face a large number of geological hazards during construction and operation.In this paper,on the basis of collecting geological disasters survey and design data related to important ground structures?subgrades,bridges,stations,tunnel entrances?of the Dusi Railway,first of all,the development and distribution of geological disasters in the study area of the Dusi Railway are studied to analyze the pregnancy Disaster environment and induced conditions,find the interaction between geological disasters and important railway structures;secondly,for different types of geological disasters,establish a risk assessment model of geological disasters,and use the AHP method to separate the different types of geological disasters Disaster risk assessment;finally,based on ArcGIS,the linear hazard assessment and zoning hazard assessment of the geological disasters of the Dusi Railway were carried out,and the comprehensive analysis obtained the risk assessment results of the important geological hazards threatened by the important structures on the ground of the Dusi Railway.Through research,the main achievements and understanding of the following aspects are obtained:?1?Through the study of the development and distribution of ground geological disasters along the Dusi Railway,disaster-preventing environment and induced conditions,there are five types of geological disasters in the study area,namely landslide,avalanche,debris flow,rock pile,and dangerous rock Falling stone.Geological disasters are mainly concentrated in the territory of Wolong Town,located in the Alpine Gorge area of Longmen Mountain,and are characterized by seasonality,repeatability and high incidence of earthquakes in terms of time distribution.The disaster-preparing environment for geological disasters mainly includes topography,vegetation development,altitude,stratigraphic lithology,geological structure and other factors;the inducing conditions include rainfall,earthquake,freeze-thaw,groundwater,surface water,river influence,etc.The important ground structures threatened by geological disasters include railway subgrades,bridges,tunnel openings and stations.The construction of the Dusi Railway will also trigger geological disasters or exacerbate the risk of geological disasters.?2?Construct a geological hazard risk assessment model along the Dusi Railway,that is D=₁×₂,where P₁ is the geological hazard susceptibility score and P₂ is the geological hazard arrival railway probability score.According to the type of geological disasters and the characteristics of disasters in the study area,select appropriate evaluation indicators to quantify and assess the susceptibility of various geological disasters;according to the possible movement distance of geological disasters and the distance between geological disasters and railways,establish The evaluation method of the probability of the disaster reaching the railway;summarizing the mileage station data of the geological disasters and the width of the leading edge of the disaster points to obtain the range of the railway lines affected by the geological disasters.?3?Using the risk assessment model of landslide geological hazards on the Dusi Railway,a risk assessment was conducted on 21 landslides in the study area.The results were 4 extremely high hazards,8 high hazards,7 medium hazards,and 2 low hazards;The risk assessment results of the 42 collapses in the area are:11 extremely high risks,12 high risks,14 medium risks,2 low risks,and 3 extremely low risks;the risk assessment evaluation results of 31 debris flows in the study area are::4extremely high hazards,10 high hazards,4 medium hazards,10 low hazards,3extremely low hazards;the risk assessment results of 24 rock piles in the study area are:6 extremely high hazards,6 high Dangerous,8 medium-dangerous,2low-dangerous,and 2 extremely low-dangerous;the risk assessment results of 20dangerous rocks and falling rocks in the study area are:8 extremely high-risk,3high-risk,5 medium-dangerous,and 3 Low risk,1 extremely low risk.?4?Based on ArcGIS,geological hazard linear risk assessment and geological hazard zoning risk assessment were conducted in the study area.The result of linear risk assessment of geological disasters on the Dusi Railway shows that the railways are mainly exposed to extremely high-risk geological hazards,followed by high-and medium-risk geological hazards,and a small number of railway structures encounter low-and extremely low-risk geological disasters.Threat.The extremely high-risk and high-risk disasters are mainly distributed from the area of Shangmujiangping Bridge to Gengda Station,the exit of Cailinte Bridge to Dengshenggou Tunnel,and the area of Siguniangshan Station.The risk assessment results of the geological hazard zoning of the Dusi Railway show that the extremely high-risk and high-risk areas are mainly distributed from the Shangmujiangping Bridge to Gengda Station,Wolong Station to Dengshenggou Tunnel Exit,and the Siguniangshan Station area.The area is mainly distributed near the Maoxian-Wenchuan fault zone and the high-altitude Siguniangshan station.From Dujiangyan Station to Siguniangshan Station,the whole line passes through medium,low risk-high,very high risk-medium,low risk-high,very high risk-medium,low risk-high,very high risk,the degree of disaster risk Different areas.Comparing the linear hazard assessment of the geological hazards of the Dusi Railway and the results of the hazard assessment of the zoning of the Dusi Railway,it can be seen that the geological hazards with high risks are mainly distributed from the Shangmujiangping to Gengda Station,Wolong Station to the Dengshenggou Tunnel Exit In the area of Niangshan Station,the evaluation results of the two are basically the same.?5?Analyze the risk level and number of important structures?bridges,roadbeds,tunnel entrances,and stations?of the Dusi Railway in the range of relevant geological hazards in the linear risk assessment results,and the location of important structures in the zoning risk assessment results Hazardous area.The comprehensive evaluation results of the risk of geological hazards threatened by the important structures along the railway transportation poverty alleviation project from Dujiangyan to Siguniangshan Mountain provide a scientific basis for the disaster prevention and mitigation design of the railway transportation.