A Study On Lability And Risk Zoning Of Geological Disasters In Xixiang County

Xixiang county is located in Qinba mountain area.In recent years, with the humanconstruction activities intensified, the geological disasters frequently occurred,So humanbeing’s life and wealth are seriously threatened.This thesis, based on fully gathering physiogeological as well as geology geologicenvironment information of Xixiang county and combining them with investigation outeomesof geological hazard sites,analyzes the developing features and forming mechanisms ofgeological hazards,and develops lability zoning with comprehensive evaluation based on GIS.On a base of lability zoning and considering risk degree of geological disasters,this thesisachieves risk zoning.The last result is basically tallies with the practical situation. The corecontents of this thesis are listed as follows:(1)This thesis analyzes developing features,distribution character and forming conditionsof geological disasters in Xixiang county. The main hazards in Xixiang county includeslide,landslide, surface collapse and mudflow. Distribution character in Xixiang county isdifferent from area to area.Geological hazards are very scarce in middle mountain and hillarea,while they are richly developed in low mountain and basin area and are unbalancedbetween each town.The developing features are summarized as group character,periodicproperty and unplanned property.The forming conditions are introduced from foundationfactors and dynamic factors. The foundation factors are landform and geomorphy，rock soilmass types,geological structure,while the dynamic factors are made up of waterfactors,earthquake and human engineering activities.(2)The evaluation set has four-stage standard,that is to say the lability degree ofgeological disasters is divided into high lability,middle lability,low lability and none lability.Evaluation index system is set up by choosing seven concrete evaluating indicators,includingdegree of slope, morphologic type,rock soil mass types, geological structure,vegetationcoverage rate,rainfall and human engineering activities,the weight of each evaluation index is calculated with A.H.P, and gained lability zoning graph by using spatial analysis of ArcGIS.(3)By means of superimposing the outcome of lability zoning and risk degree ofgeological disasters,this thesis realizes risk zoning.