Ground Deformation Characteristics And Stability Evaluation Of Goaf In Xiahuayuan Coal Mine,Zhangjiakou

The mining of underground resources has created underground goafs,which cannot be filled and treated in time,resulting in ground subsidence and cracks in structures,which will seriously affect the production and life of residents,and even hinder the urban economy development of.Therefore,research on geological disasters and prevention in goafs in cities and towns is of great significance.This paper is based on the Zhangjiakou Xiahuayuan Coal Mine Goaf Management Project,by use comprehensive means such as field investigation,geophysical prospecting,drilling,on-site monitoring and theoretical calculation analysis,to study the ground deformation characteristics and hazards of the Zhangjiakou Xiahuayuan Coal Mine.Here are the main conclusions :(1)On the basis of on-site investigation of the geological environment conditions of the study area.By the transient electromagnetic method,high-density electrical method and shallow seismic method as the mainstay,supplemented by drilling verification,the spatial distribution range and depth of the mined-out area in Xiahuayuan were basically ascertained.(2)A monitoring plan for ground deformation in the goaf of Xiahuayuan was designed and on-site monitoring was implemented.According to the statistical analysis of 7 times of monitoring data in the goaf from May 2016 to July 2019,the ground subsidence rate and cumulative subsidence of the goaf are obtained,and the law and cause of ground deformation are analyzed.(3)According to the geological conditions of the project area and the distribution characteristics of goaf,the probability integration method is used to establish the ground deformation model,determine the calculation parameters,the ground deformation is predicted mainly from four aspects: subsidence value,horizontal displacement,curvature and inclination of the ground.On this basis,according to the principles of qualitative and quantitative risk classification,the mined-out areas of the lower garden are classified into different levels,namely,dangerous areas,more dangerous areas and relatively stable areas.(4)According to the ground deformation monitoring data of the goaf and the calculation results of ground movement and deformation,the prevention and control measures for the damage to the buildings in the goaf are proposed,including measures to prevent or reduce the influence of the goaf on the existing buildings and prevent the goaf from affecting the existing buildings.New building deformation measures,etc.