综放沿空掘巷护巷窄煤柱留设宽度优化设计研究

护巷窄煤柱的合理留设是综放沿空掘巷技术成功实施的关键问题。基于采空侧煤体倾向支承压力分布特征以及护巷煤柱体的极限平衡理论,确定了护巷窄煤柱合理留设宽度的上、下限值解析表达式,结合山东某矿3309综放工作面的采矿地质条件,认为护巷窄煤柱合理留设宽度范围为4.1~7.2 m。为了进一步优化设计护巷窄煤柱的留设宽度,采用数值模拟方法对合理取值范围内的护巷窄煤柱留设宽度进行对比分析,认为3309综放工作面护巷窄煤柱的最优留设宽度为5m。将上述研究成果成功运用于工程实践,现场实测数据表明,结合理论分析和数值计算综合确定的护巷窄煤柱最优留设宽度可以有效控制沿空巷道围岩变形量,有利于维护综放沿空巷道的整体稳定性。

Width optimization of narrow coal pillar of roadway driving along goaf in fully mechanized top coal caving face

The width of the narrow coal pillar of roadway driving along goaf is the key factor affecting the surrounding stability of the mining roadway in fully mechanized top coal caving face. Based on the abutment pressure distribution characteristics and the ultimate balanced theory, the reasonable width of narrow coal pillar should be chosen between 4.1m and 7.2 m, combined with the engineering condition in workface 3309 of a mine in Shandong. In order to optimize the width of the narrow coal pillar, the effect of plastic area distributions and stress distribution characteristics of the two sides of coal pillar under conditions of different width of narrow coal pillar have been studied by numerical analysis. The optimal width of coal pillar is 5 m. The validity of the optimal coal pillar width was verified by the en-gineering practice in workface 3309. Field monitoring has indicated that the surrounding rock defor-mation of the mining roadway could meet the requirements of safety production.