Study On Geophysical Comprehensive Exploration Method Of Coal Seam Goaf In LZC Area Of Inner Mongolia

With the long-term and large-scale exploitation of coal resources,while bringing enormous economic and social benefits,over-exploitation has also resulted in a large number of goafs in many areas,resulting in large-scale surface subsidence,serious damage to surface buildings,transportation facilities,living infrastructure,land,and so on,which has given the people of mining areas a livelihood.Life and production pose a great threat to China's economic construction and social stability.Therefore,it is of great significance to study the comprehensive geophysical exploration method for goaf in coal seam.On the basis of systematically collecting and sorting out the related literature of coal seam goaf exploration technology at home and abroad for many years,this paper firstly summarizes the concept,classification,geological characteristics and geophysical characteristics of coal seam goaf.Then,taking Inner Mongolia LZC region as an example,comprehensive geophysical exploration of coal seam goaf was carried out by using controllable source audio magnetotelluric method,transient electromagnetic method and three-dimensional seismic method,and the location and scope of goaf or its affected area were delineated respectively.Finally,combined with the data of drilling,geophysical logging and ground investigation,the accurate distribution characteristics of goaf are determined,which provides a powerful basis for the cause analysis of ground and building cracks in this area,the adjustment of land use planning and the mediation of social conflicts.This thesis research thinks,the resistivity of LZC areas mined-out area of Inner Mongolia and the evident differences between wave impedance and surrounding rock,goaf on the electromagnetic method to detect profile characterized by high apparent resistivity anomaly,in reflection seismic profile for the weak or clutter reflection characteristics,the apparent differences and characteristics for electromagnetic method and 3D seismic method for detecting goaf laid the premise condition.Controlled source audio-frequency magnetotelluric method and transient electromagnetic method electromagnetic detection methods,such as acquisition speed,good efficiency,strong adaptability,can marking out with abnormal high resistance characteristics of mined-out area or the impact area,but as a result of mined-out area difference between anomalies and its affected area is not large,not scope of mined-out area and its influence zone for further screening,thus unable to accurately determine the goaf or goaf affected zone,and 3D seismic detection method can distinguish between goaf and its affected area,can accurately detect the location of the mined-out area,has high precision,but its high cost,construction period is longer,In practical work,the two methods should be combined.Firstly,electromagnetic method should be used to delineate the goaf or the approximate distribution range of its affected area,and 3d seismic method should be used to accurately measure the distribution range and burial depth of the goaf,so as to improve the accuracy of exploration results.The research results of this paper show that the location and scope of goaf in Inner Mongolia LZC area are basically consistent with the data provided by the mining party.The goaf is all distributed to the east of the safety coal pillar in the east of the exploration area,and no goaf has been found in the west of the safety coal pillar.The paper has 72 pictures,9 tables,and 78 references.