Considering the continuous development of gob side entry driving technology, the influence of roof fracture on coal pillar is difficult to be accurately predicted. In order to explore the fracture structure characteristics of the overlying multi thick hard rock strata and its influence on coal pillars, the stress analysis tests of coal pillars under different roof fracture positions were designed. Different fracture positions of immediate roof and high-level thick hard rock were simulated by different corresponding positions of goaf, coal pillar edge line and rotary fixture line. According to four experimental design schemes, the strain distribution of coal mine goaf under different roof fracture combination positions was obtained. By analyzing the results of digital speckle pattern experiment, the distribution range and form of stress above coal pillar and low level thick hard rock are obtained, which provides theoretical basis for studying the whole process of coal pillar fracture.
Key Words
coal pillar; digital speckle; gob-side entry driving; roof fracture
Address
Shankun Zhao and Yin Wang — 1.) School of Energy and Mining Engineering, China University of Mining and Technology Beijing,Ding 11, Xueyuan Road, Haidian District, Beijing, PR China 2.) Safety Technology Branch, CCTEG China Coal Research Institute, # 5, Qingniangoudong Road, Chaoyang District, Beijing, PR China
Qiru Sui, Cong Cao, Xuecheng Wang, Chunlai Wang and Daming Zhao — School of Energy and Mining Engineering, China University of Mining and Technology Beijing,Ding 11, Xueyuan Road, Haidian District, Beijing, PR China
Yang Zhao — Safety Technology Branch, CCTEG China Coal Research Institute, # 5, Qingniangoudong Road, Chaoyang District, Beijing, PR China
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