采场围岩能量演化及释放模拟研究
Simulation study on energy evolution and release of surrounding rock in stope
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摘要: 岩体应变能是集主应力、弹性模量、泊松比等综合物理量,能够更好地解释采矿过程中的动力现象。为揭示采动过程中采场围岩能量演化和释放规律,基于岩体应变能理论推导了能量演化与释放的计算方法,以平朔井工三矿为工程背景建立数值计算模型,模拟计算不同回采时刻采场围岩能量变化,结果表明:①采场围岩的应变能峰值随着工作面的推进而逐渐前移,煤层能量峰值主要集中于煤壁前方8 m以内,煤层的应变能相对较高,顶底板坚硬岩层中的能量值相对较低;②开挖开切眼后,开切眼上方为能量释放区,开切眼煤壁前后为能量积聚区;在该矿地质条件下,工作面正常回采时,工作面煤壁上方8 m以内为能量主要释放区域,煤壁前方2~8 m为能量主要积聚区; 因此,对于煤壁上方应及时支护,防止其能量的快速释放而引起冒顶;对于具有动力灾害倾向的煤壁前方应采取措施控制应力集中。Abstract: The strain energy of rock mass is a comprehensive physical quantity that integrates principal stress,elastic modulus and Poisson′s ratio,which can better explain the dynamic phenomena in mining process.In order to reveal the energy evolution process and release law of stope surrounding rock during mining process,a calculation method of energy evolution and releasing is derived based on rock mass strain energy theory.A numerical calculation model is established with No.3 of the Pingshuo Coal Mine as engineering background and the energy change of surrounding rock of the stope at different mining times were simulated.The results show:① The peak strain energy of the surrounding rock gradually moves forward as the working face advances,and the peak of coal seam energy is mainly concentrated within 8 m in front of the coal wall; The strain energy of the coal seam is relatively high,and the energy value in the hard rock layers of the top and bottom is relatively low;② After excavation,the energy release zone is above cut-eye,and the energy accumulation zone is in front and behind the cut-eye; In terms of local quality conditions,when the working face is in normal mining condition,the main energy release zone is within 8 m above the coal wall of the working face,the main accumulation zone of energy is within 2~8 m in front of the coal wall.Therefore,it is necessary to support the coal wall timely to prevent the roof falling caused by the rapid release of its energy,and to take measures to control the stress concentration in front of the coal wall with the tendency of dynamic disasters.