Abstract
With the reduction and depletion of shallow energy, the mining depth of coal around the world is increasing year by year, and the mining depth of some coal mines in China has reached kilometers. The main roadway near the goaf with the deep high static stress is very easy to be damaged after being disturbed by the mine earthquake. Taking the main roadway in the no. 1 mining area of Gaojiapu coal mine in Binchang mining area, Shaanxi Province, China, as the engineering background, the high-energy mine earthquake monitored by the on-site microseism is equivalently simulated through the dynamic module of FLAC3D, and the spatial-temporal rotation characteristics of the principal stress of roadway surrounding rock under the disturbance of mine earthquake are studied and analyzed and put forward corresponding prevention and control measures. Research shows early stage of mine earthquake disturbance, roadway roof is first affected, and the principal stress of the roof has the trend of deflection to the side of the goaf. In the middle stage of mine earthquake disturbance, the main body of roof principal stress deflects to the side of goaf, and the deflection range is large. In the later stage of mine earthquake disturbance, the principal stress directions in the surrounding rock reverse rotation, and the reverse rotation angle of the principal stress direction in the roof is the largest. Finally, the asymmetric distribution characteristics of principal stress rotation are verified by using the asymmetric deformation phenomenon on both sides of roadway surrounding rock. Based on the rotation characteristics of principal stress under the dual influence of mine earthquake disturbance and goaf, optimize the layout scheme and blasting parameters of blasting pressure relief holes. The transmission direction of principal stress can be changed by blasting pressure relief method; meanwhile, the transmission of principal stress can be blocked; through the comparison of microseismic activity law before and after pressure relief, pressure relief effect is good. The research results can provide a certain reference basis for coal mine roadway pressure relief and reducing disaster conditions.
Highlights
Energy and mineral resources are important factors restricting the national economic development of all countries in the world; with the reduction and depletion of shallow resources, the mining depth of coal all over the world is increasing year by year [1,2,3]
The mining depth of coal mines in China is increasing at the rate of 8~12 m per year; the eastern mine develops at the rate of 100~250 m every ten years; it is estimated that in the twenty years, many coal mines will enter a depth of 1000~1500 m
Gaojiapu coal mine is located in the northwestern part of the Binchang mining area in Shaanxi Province, China; it is the second pair of modern large-scale mines developed and constructed by Shandong Energy Zikuang Group in Binchang mining area, Shaanxi Province
Summary
Energy and mineral resources are important factors restricting the national economic development of all countries in the world; with the reduction and depletion of shallow resources, the mining depth of coal all over the world is increasing year by year [1,2,3]. Niu et al [20] with the help of self-developed three-dimensional stress testing elements reveal the true loading and unloading stress path of surrounding rock at different depths of deep roadway and the stress state before and after excavation; the evolution law of the principal stress difference of surrounding rock inside and outside the loose zone is mainly analyzed, and combined with the failure range and mode of surrounding rock, its mechanism is discussed. Li et al [21] studied the variation law of the direction of the principal stress field of the surrounding rock on the side of the goaf and its influence mechanism on the distribution of plastic zone of surrounding rock along goaf roadway; the mechanism of nonuniform large deformation of deep goaf roadway is revealed. The research results can provide a certain reference basis for coal mine roadway pressure relief and reducing disaster conditions
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