Abstract
High-efficiency maintenance and control of the deep coal roadway roof stability is a reliable guarantee for safe production and sustainable development of a coal mine. With belt haulage roadway 3108 in MenKeqing coal mine as the research background, in situ investigation, theoretical analysis, numerical simulation, and engineering practice were carried out to reveal the law of improving the bearing state of bolts by increasing the thickness of the roof anchoring layer. Also, the mechanism of the high-efficiency and long anchoring of the roof is revealed. Results show that increasing thickness of the roof anchorage layer could mobilize deep rock mass to participate in the bearing and promote the bolt to increase the resistance in a timely manner to limit the deformation of rock mass. Through the close link between shallow soft rock mass and deep stable rock mass, the deformation of the shallow rock mass is well controlled and so are the development and expansion of the roof separated fissures from shallow to deep. Long high-performance sustainable bolt technology for roof are proposed and carried out to control the stability of the deep roadway roof. Engineering practice indicates that deformations of roof could be efficiently controlled. The maximum deformations of the roof and sidewall-to-sidewall are 17 mm and 24 mm, respectively. No obvious separation fissures are found in the anchoring range of roof. This study provides a reference for roof stability control of deep roadway under similar conditions.
Highlights
Coal resources play a supporting role in China’s economic development
The axial force in free section of the bolt increases step by step. This is mainly because with the increase of bolt length, the end of the bolt is anchored in the stable rock stratum gradually through the roof fissure circle layer, and the decrease of displacement of the rock mass at the end of the bolt leads to the increase of difference of the displacement within the anchorage range
Given that the working resistance of the bolt is determined by the difference of rock mass deformation within the anchorage range of the bolt, as a result, the working resistance of the bolt increases with the increase of bolt length
Summary
Coal resources play a supporting role in China’s economic development. With the gradual exploitation of shallow resources [1,2,3], the exploitation of deep buried resources has become an inevitable trend in China’s coal mining. Xie [13,14] discussed the mechanical characteristics and energy dissipation law of different high ratio coal rock structure from the perspective of energy release and dissipation and put forward two roof support principles, successfully applying this to the test roadway. Qin [15] used the method of theoretical analysis and numerical simulation to systematically study the distribution characteristics of the roof bearing structure of the deep soft rock roadway and proposed and successfully applied the roof reinforcement scheme of the deep dynamic soft rock roadway. Guo [18] used the pressure arching theory and numerical simulation method to study the deformation and instability mechanism of a large-span complex roof under deep-buried condition, designed and successfully applied the support scheme of “anchor (cable) + metal mesh + M-strip + single-prop”. This study provides a reference for roof stability control of deep roadway under similar conditions
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