Exploration And Hazards Analysis Of The Coal-mining Area For A High-speed Railway Alignment

In recent years,the large-scale mining and unreasonable management of various mining areas have resulted in a large number of mined-out areas in the ground.The existence of these mined-out areas will lead to the occurrence of ground subsidence,ground fissures,collapses,mine earthquakes and waterlogging.Furthermore,the existence of mined-out area is also a threat to surface buildings,transportation lines,the safety of life and property of residents.With the rapid development of high-speed railway,the presence of mined-out area will seriously affect the selection of high-speed railway line in the process of railway survey and design,which is also one of the main unfavorable geologic bodies restricting railway alignment.By referring a large amount of papers and documents,this paper systematically summarizes the surface deformation,hydrology,density and geophysical characteristics of the mined-out area and systematically analyses the usual hazards,such as surface subsidence(ground subsidence,ground fissure and collapse),water leakage,landslide,coal mine earthquake,gas outburst and explosion and so on,and discusses its main hazard factors,which includes geology,hydrogeology,geometric factor and other factors.On the basis of what we mention before and combine a case study of the evaluation and management of a high-speed railway project in Shanxi province.Firstly,this paper researches efficiency of the mined-out area exploration by using the integrated geophysical method is studied.From the basic of the geophysical method,the application of transient electromagnetic method and seismic imaging method to the exploration of mined-out area in this area is expounded.Based on the interpretation of synthetic geophysical data,four shallow mined-out areas were found in the study area,which verified the buried depth and distribution characteristics of the mined-out area in the study area.It was confirmed that the integrated geophysical method was applied to the high-speed railway project area.And the characteristics of the electrical and elastic waves of the mined out mines are analyzed,which provides the basis for the popularization and application of the above two kinds of geophysical methods in the exploration of the mined-out area.Secondly,the manual method,the train load stability,the method of roof collapse analysis,arching analysis,roof thickness partitioning method and two belt height estimation method are used to evaluatethe stability of the overburden roof of the mined-out area above the line.The ground subsidence,ground fissures,subsidence,water inrush and water seepage and mine quake,which are in the study area are predicted by combining the characteristics of regional natural geography,geology and hydrogeology,and so on,and analyzed its occurrence mechanism.Furthermore,it discusses the influence of gob through the mined-out area on the high-speed railway alignment,and provides reasonable suggestions.Finally,the paper summarizes the exploration of coal-mining area and its hazards analysis,and puts forward some possible countermeasures.