深井侧向采动应力分布规律及沿空巷道支护

Study on the distribution of side abutment pressures and ground support for double-used entries in deep mining

为探究侧向采动应力分布规律,运用弹塑性力学理论建立煤岩体侧向采动力学分析模型,同时引入Weibull分布函数,得到煤岩体侧向采动应力方程和破坏深度方程。以顾桥1126(1)工作面为背景,解出煤体侧向采动应力、应力集中系数和塑性破坏深度,并研究各因素对采动应力分布的影响,指导沿空巷道支护设计。研究结果表明:①煤体强度、界面强度、支护强度和煤厚影响煤体稳定性,煤体稳定性增高时,采动影响范围和塑性破坏深度减小,应力集中系数增大;②原岩应力和悬臂梁长度决定煤体原始受力,随煤体受力的增加,塑性破坏深度、采动应力和采动影响范围均增加。根据沿空巷道围岩状态,提出高预紧力全长锚固锚杆+锚索+钢带+金属网的非对称锚网索密集支护方案。现场实测表明:1126(1)回风巷的支护效果良好,可满足回采巷道安全生产的预期要求。

A dynamic model was developed using the theory of elastic-plastic mechanics,aiming to investigate the distribution of side abutment pressures caused by longwall-mining.The Weibull distribution function is introduced to obtain equations for calculating side abutment pressures and coal failure depth caused by mining.A case study was performed based on the geological and geotechnical conditions of the 1126(1)face at Guqiao Mining Group.The side abutment pressure,the stress concentration factor and the coal failure depth were evaluated.The factors influencing the distribution of mining-induced stress was assessed,aiming to guiding the support design of a double-used roadway.The research shows that:①Factors such as the coal strength,interface strength,support strength,and coal thickness affect the stability of the coal;when the stability of the coal increases,the mining influence range and the depth of plastic failure decrease,and the stress concentration factor increases;②The stress of the original rock and the length of the cantilever beam determine the force state of the coal.With the increase of the force of the coal,the mining-induced stress,the mining failure depth and the mining influence range all increase.Based on the surrounding rock state of the roadway along with the goaf,a support pattern was proposed the unsymmetrical bolt net cable dense support scheme of high pretension full-length anchor bolts+anchor cables+steel belts+metal meshes.Field monitoring shows that the support pattern effectively controlled the deformation of the double-used entry.