Study On The Development Characteristics And Laws Of Geological Disasters In Complex Mountain Areas

A gas field is the largest and most productive super-large marine acid gas field in China,and the produced natural gas contains high hydrogen sulfide toxic gas,which leads to high safety risks.Since the rainy season in 2020,the continuous rainfall in Puguang Town,Xuanhan County has caused various geological disasters in the study area,posing a huge threat to the lives and properties of the country and people,affecting the normal operation of the gas field and the normal life order of people around it.In order to effectively prevent and control geological disasters in the gas field and its surrounding areas,and ensure the normal operation of the gas field and the safety of the surrounding people,it is necessary to analyze the development law and formation mechanism of geological disasters in the gas field.This thesis takes various geological disasters in the study area as the research object,finds out the development types,characteristics and distribution laws of various geological disasters in the study area,summarizes the formation conditions and breeding mechanism of geological disasters on this basis,and selects typical geological disasters for specific analysis.The main achievements of this thesis are as follows:(1)There are four kinds of geological disasters in the study area: landslide,collapse,water destruction and unstable slope,among which 23 are landslide,36 are collapse,54 are unstable slope and 34 are flood destruction.(2)On the basis of analyzing the development and distribution characteristics of geological disasters in the region,the formation conditions and breeding mechanism of various geological disasters are discussed.(3)For Dawan landslide,the transfer coefficient method is used to calculate the stability of the profile under various working conditions: under natural working conditions,the whole landslide is in a stable state;But in the case of heavy rainfall,the stability of the landslide will decline,shear failure along the shear front and secondary shear front is easy to occur,the formation of landslide.(4)The ABAQUS software was used for numerical simulation,and the strength reduction method was used to obtain that the stability coefficient of the model under natural conditions was 1.15,which was in a stable state,and the stability coefficient under rainstorm conditions was 1.08,which was in an unstable state.The simulation results were basically consistent with the above results.(5)Using PFC2 D software for motion simulation of the 3-3 'profile,it is concluded that the landslide early by leading edge slope foot are the first deformation failure,failure characteristics with time gradually increased,and showed the trend of the development of the flange drawing back,failure mode of soil mass along its internal shear failure produces the conclusion of the failure modes of the slip surface,the simulation results are in conformity with actual situation.