Law Of Evolution And Application About Stress Field Of The S Urrounding Rock In Deep Well Mining Influenced Space

Under deep mining conditions, the law of face’s rock broken、deformation、 movement compared with shallow coal seam had larger change. Especially the stress of surrounding rock is elevated, the influence of underground tunnel and chamber is increasing. Compared with the research of shallow coal seam, our research on the deep coal seam is far from enough. In this paper, taking1231(1) working face of Huainan Mining Bureau Pan Yi-dong11coal as the research background. Discussion on the roof overburden movement law in mining process and the country rock stress state. The coal seams have a thickness averaging2.45m, at a burial depth of-778.3～-839.1m, roadway located in the high stress area, also the surrounding rock deformation and failure is very serious. In the deep mining conditions, rule of overburden failure, deformation, moving has changed a lot relative to shallow coal seam. Our study of the deep coal mining is still far from enough compared with the research of shallow coal seam. The main conclusions are as follows:(1)A crustal stress test was made in1231(1) working face coal return-rise by stress relief method. The maximum principal stress was23.72Mpa while the minimum principal stress was16.85Mpa.The pore side pressure coefficient was1.41.The main stress in this area was tectonic stress.(2)1231(1) of the Pan Yi-dong mine working face similar simulation experiment was carried out, after mining in working face, immediate roof first caving step distance is30cm, roof first weighting step distance is40cm, the periodic weighting step distance is about9-15cm, goaf overburden rock fracture had experienced a development, development, fracture compaction rich stages. According to the working surface of surrounding rock stress change rule in mining process, the face of surrounding rock can be divided into five parts:mining did not affect the area; stress increased area; stress decreasing area; pressure increased area; compaction area.(3) On the basic of mining geological conditions, the study about the changes of the surrounding rock stress during mining was made by numerical simulation software. As the working face advancing, the range of3-15m was stress dramatically increased region, the range of15-40m was stress increased significantly region and the range of40-100m was stress increased region. The pressure relief height of the overlying strata tends to be80～120m while the floor pressure relief area beneath the floor about100m.A inverted ear shape stress increased region came across with a distance of3～35m to the crossheading in two side of the gob whose width was25-35m and height was40～60m.