| Guizhou Province is one of the provinces with the most serious geological hazards in China.It has the characteristics of wide distribution area,large quantity,small scale and large loss.In recent years,many catastrophic landslides and landslides have occurred,resulting in serious casualties.It is urgent to carry out research on risk assessment and control of geological hazards so as to reduce the potential risk of geological hazards.Because of its karst geomorphological characteristics,the main geological hazards in Guizhou Province are landslides.Collapse and geological disasters are generally characterized by high elevation,steep terrain,complex genetic mechanism,and sudden bursting.It is difficult and low precision to identify,evaluate stability and delineate dangerous areas by conventional means.In this paper,a multi-temporal satellite remote sensing monitoring,InSAR time series analysis,three-dimensional aerial survey of drones,detailed field survey and other technical means are used to construct a set of technical methods for risk assessment and control of village collapse geological disasters,including early identification of the source of collapse geological disasters,risk assessment,vulnerability assessment,risk assessment and risk management and control,and the demonstration of the collapse zone in Mangling Town,Guizhou Province,led to the following main research results:?1?Taking advantage of the“Three Inspections”system—“Space Inspection,Sky inspection,Ground inspection”proposed by Professor Xu Qiang and other scholars from the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection of Chengdu University of Technology,including“normal inspection”using high-resolution optical remote sensing and InSAR,“detailed inspection”using airborne LiDAR and photographs taken by UAV,and“verification”made by the ground department,remote sensing identifies and recognizes major geological hazards in susceptibility locations from different prospective and scales,and then take precautions against them accordingly.The paper mainly uses InSAR to detect surface deformation in order to identify,monitor and analyze the susceptibility zones in Zongling town.?2?A statistical analysis of typical collapse events in Guizhou Province in recent years was carried out,and an improved formula for calculating the maximum motion distance?Lmax?of collapse was established.When the collapse volume is greater than 105 m3,Lmax==H/10-0.109 log V+0.17;When the volume is less than 105 m3,Lmax==H/10-0.109 log V+0.22.This formula has a good predictive effect on the maximum movement distance of geological disasters in Guizhou Province.?3?The paper establishes hazard assessment system and quantitative method for collapse.Based on landslide features in rural areas,the author chooses 8 factors including slope crack deformation,run-out extent,slope angle,slope height,structural plane,slope structure,excavation activity,and precaution measures.After assigning particular weights to these factors by experts and determining the weights using hierarchy analysis method,the author establishes hazard assessment model which can be used to determine hazard classes.In this way,scholars can quickly determine the collapse hazard class with the help of the formula.?4?Using UAV to shoot the elements at risk in susceptibility zones.Based on the3-D model built up by Smart3D software,the paper analyzes the elements at risk by using tilt survey method.The advantage of this method is that we can achieve basic data?building structure,number of layers,value etc.?such as the height and contour of the surface features with the help of algorithm and aerial photographs.It can also reduce field investigation workload and time,and make accurate analysis of the elements at risk.The author also establishes a quantitative method for quickly extracting the elements at risk based on tilt photogrammetry.?5?Considering that the distance between the disaster-receiving body and the collapse source area is different,the degree of damage caused by the collapse disaster is different.This paper introduces the concept of exposure to evaluate the vulnerability of the disaster-bearing body.Vulnerability=?Elements at Risk×Exposure Degree..Using the statistical probability of the collapse angle of arrival,the exposure of the disaster-bearing body is divided into three levels:high?10.5?,medium?0.50.25?,and low?0.250?,respectively corresponding to the arrival angle>21°,16°21°and<16°??6?Based on the cases which are very successful in group detection and prevention,professional monitoring,and geological disaster real-time monitoring system etc.,the author puts forward“four-point integration”monitoring system and“five in one”integrated disaster prevention system in the landslide disaster management in Zongling town.All the departments,local governments,and the people should work together to prevent landslide disasters in order to reduce losses and ensure people's lives and property. |
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