Abstract
In order to prevent the multi-dynamic disasters induced by rock burst and roof water inrush in strong rock burst coal seams under multi-aquifers, such as is the case with the 207 working face in the Tingnan coal mine considered in this study, the exhibited characteristics of two types of dynamic disasters, namely rock burst and water inrush, were analyzed. Based on the lithology and predicted caving height of the roof, the contradiction between rock burst and water inrush was analyzed. In light of these analyses, an integrated method, roof pre-splitting at a high position and shattering at a low position, was proposed. According to the results of numerical modelling, pre-crack blasting at higher rock layers enables a cantilever roof cave in time, thereby reducing the risk of rock burst, and pre-crack blasting at underlying rock layers helps increase the crushing degree of the rock, which is beneficial for decreasing the caving height of rock layers above goaf, thereby preventing the occurrence of water inrush. Finally, the proposed method was applied in an engineering case, and the effectiveness of this method for prevention and control of multi-dynamics disasters was evaluated by field observations of the caving height of rock layers and micro-seismic monitoring. As a result, the proposed method works well integrally to prevent and control rock burst and water inrush.
Highlights
Rock burst is one of the serious mining hazards threatening the safety, economics and productivity of underground engineering around the world, such as in coal mines, metal mines, waste repositories, etc. [1,2] and has occurred in civil tunnels in recent years [3,4]
This paper considered the 207 working face in the Tingnan Coal Mine as a study example, combined theories with numerical simulation and field work technologies to analyze the key contradiction between rock burst and water inrush, proposed an integrated method, and put the method into practice, which has gained certain achievements
The depth of the No 4 coal seam is between 508 m and 680 m; in light of this, the hazard index of rock burst increases from 0.1 to 0.45, which suggests that the mining depth is a key factor for rock burst
Summary
Rock burst is one of the serious mining hazards threatening the safety, economics and productivity of underground engineering around the world, such as in coal mines, metal mines, waste repositories, etc. [1,2] and has occurred in civil tunnels in recent years [3,4]. Jiang et al [16,17,18] studied the stress evolution rules of a multi-aquifer and a coal seam in light of the dynamic phenomenon during the process of drainage in the deep roadway of the Ordos mining area and revealed the mechanism of rock burst induced by drainage. This paper considered the 207 working face in the Tingnan Coal Mine as a study example, combined theories with numerical simulation and field work technologies to analyze the key contradiction between rock burst and water inrush, proposed an integrated method (roof pre-splitting at a high position and shattering at a low position), and put the method into practice, which has gained certain achievements
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