Study On The Regularity Of Disasters Caused By Repeated Mining Of Multiple Coal Seams In Hancheng Mining Area

In recent years,repeated mining of multiple coal seams in deep underground areas has exacerbated the movement and deformation of overlying rock formations and the surface,caused greater deformation of the construction(structures)in the area affected by mining,caused serious damage such as cracks,landslides,collapse and landslides,further causing degradation of land resources and ecological environment in mining areas,and seriously affected the normal living standards of the people in mining areas,At the same time,it also leaves great hidden dangers for the future infrastructure of mining areas,so it is necessary to study the law of disaster caused by repeated mining in deep coal seam.The research on the subject will provide reference for the mining of 21504 and other working faces,and it is of great theoretical and practical significance to guide the "three falls" coal mining,the reasonable retention of society to protect coal pillars and the arrangement of mining areas,the reduction of ground disasters,the protection of ecological environment and the mainten,ance of social stability.This paper analyzes and studies the observation data and research results of the predecessors in Hancheng mine area.Based on this,a surface movement observatory for 21505 working face in Xiangshan mining area in Hancheng was set up.After several regular observation and data processing,analyzing,studied the basic rules of surface deformation under the influence of repeated mining in deep coal seams and obtained the parameters of surface deformation and compared with the initial mining parameters.At the same time,a large number of field damage phenomenon in the mining area were investigated and analyzed.The relevant data of surface cracks and house damage caused by mining area were collected,and combined with the basic rule and the parameters of surface movement and deformation in this research area,the genesis mechanism of surface construction under repeated mining influence is further studied,and the basic rule of repeated mining in multi-coal seam is obtained.The main results are as follows:(1)Based on the typical mountainous area of hancheng mining area,the comprehensive monitoring network of surface movement and ground fracture development was established on 21505 working surface;(2)The main influencing factors of repeated mining and housing cracks in mountainous areas with multi-coal seams were analyzed.Based on the field survey data,the function relation between the development and mining speed,geotechnical ratio,surface deformation and the damage form and cause of the cracks are analyzed;(3)The paper studies the damage rule of multiple coal seam re-mining in Hancheng mining area,and compares and analyzes the damage rule of re-mining in different areas(mountainous areas).