| The southeast region of Jilin Province is located in the Changbai Mountain structural belt,where geological environment is complex and fragile and geological disasters are widely developed.In August and September 2020,three consecutive typhoons brought heavy rainfall once in 60 years.Such extreme rainfall events could easily induce geological disasters in the relatively fragile geological environment,greatly increasing the disaster hidden danger in the southeast mountainous area of Jilin Province.The treated Fusong landslide in the southeast of Jilin Province was deformed by the extreme rainfall caused by typhoon.Therefore,this paper takes Fusong landslide as the research object,mainly based on SBAS-In SAR technology,limit equilibrium theory and FLAC3D numerical simulation method,quantitative analysis of landslide deformation and stability.The conclusion is as follows:(1)According to the field geological survey,Fusong landslide has a plane shape of nearly arm-chair,and it is a medium-sized soil landslide.In 2020,after three times of extreme rainfall,obvious tensile cracks were found in the landslide body,with signs of overall deformation and potential sliding hazards.Therefore,it is necessary to strengthen the monitoring of governance and supplement governance measures.(2)The historical deformation information of the study area was obtained by SBAS-In SAR technology,and the coherent points with negative deformation rate mainly appeared on the landslide.Through the analysis of the deformation characteristics of the study area by superimposed rainfall data with time series curves,it is found that the landslide deformation has obvious seasonality,and the time period of subsidence in the middle of the landslide is coupled with the time period of high rainfall,which indicates that rainfall is the main inducing factor of the landslide deformation.(3)By using limit equilibrium method,three typical profiles of Fusong landslide are selected to analyze the stability of the landslide under different working conditions.Theof landslide is 1.156-1.176 under natural working condition,indicating that the landslide is in a stable state.Under the condition of rainstorm,is 1.018-1.049,indicating that the landslide is in an understable state.After treatment,the anti-sliding stability coefficient of landslide reaches 1.15 under natural condition and 1.05 under rainstorm condition,indicating that the landslide is in a stable state.In 2020,from the end of August to the beginning of September,the heavy rainfall caused by three typhoons was once every 60 years,which was an extreme emergency event.Under the condition of extreme rainfall,the stability was checked by using the limit equilibrium method.The landslide was in an unstable state,and the treatment project failed to meet the requirements,so it was necessary to remedy the landslide treatment project.(4)FLAC3D numerical simulation software was used to simulate and analyze the natural condition and rainstorm condition before landslide treatment,and the natural condition,rainstorm condition and extreme rainfall condition after landslide treatment.Extreme rainfall is the main factor inducing the overall deformation of Fusong landslide. |
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