特厚煤层分层开采采空区下分层大断面开切眼支护技术研究

Study on support technology of large-section open cut in lower seam layer under the goaf of layered-mined extra-thick coal seam

针对神东矿区大柳塔煤矿特厚煤层分层开采采空区下分层大断面开切眼掘进极易出现顶板冒落、片帮、底鼓等开切眼巷道大变形失稳问题,采用离散元数值模拟方法建立大断面开切眼开挖数值模型,得到了采空区下大断面开切眼开挖后围岩位移场、裂隙场和应力场演化特征,在分析大断面开切眼变形破裂力学演化机理的基础上提出了大断面开切眼掘进围岩控制对策和支护方案,数值模拟和井下工程应用结果均表明该支护方案取得了非常好的支护效果,保证了工作面的安全掘进和正常回采,为特厚煤层分层开采下分层大断面开切眼在上分层综采极近采空区下安全掘进提供了一种强力支护新技术。

Aiming at the problem of large deformation and instability of large-section cut roadway such as roof caving,sidewall and floor heave in the layered large-section open cut excavation under the goaf of upper seam in Daliuta Coal Mine in Shendong mining area,the discrete element numerical simulation method is used to establish the numerical model of large-section open cut excavation,and the evolution characteristics of surrounding rock displacement field,fracture field and stress field after large-section open cut excavation under the goaf are obtained.On the basis of the analysis of the evolution mechanism of deformation and fracture mechanics of large-section open cut,the surrounding rock control countermeasures and support scheme for large-section open cut excavation are put forward.The numerical simulation and underground engineering application results show that the support scheme has achieved very good support effect and ensured the safe excavation and normal mining of the working face,it provides a new strong support technology for the safe excavation of the lower layered large-section open cut under the very near goaf of the upper layered fully mechanized mining.