双巷布置留巷围岩塑性区演化规律及补强支护技术
Plastic zone evolution law and enhanced support technology of surrounding rock in gateway retained along goaf with double gateway layout
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摘要: 为解决红庆梁矿双巷留巷在一次采动后围岩失稳的问题,通过数值模拟对2次采动影响下的主应力差值分布特征及留巷在不同应力阶段下的塑性区特征进行研究。结果表明:留巷围岩主应力差值在一次采动和二次采动影响下经历了5个阶段,且呈现出阶段性增加的特征;留巷围岩在一次采动期间顶板塑性区由1.2 m增大到2.1 m,煤壁帮和煤柱帮塑性区由0.5 m分别增大到2.0 m和1.5m,在受二次采动应力影响后塑性区的扩展呈非对称的特点,顶板塑性区在煤柱帮侧塑性破坏较多,破坏深度可达3.0 m,两帮塑性破坏较对称,塑性破坏范围可达2.5 m。最终提出针对性的补强支护措施,现场应用后围岩顶底板移近量减小了38%,两帮移近量减小了36%,维护了巷道围岩的稳定。Abstract: In order to solve the surrounding rock instability problems occurred in the gateway retained along the goaf in a layout of the double gateways of Hongqin gliang Mine, the numerical simulation was applied to the study on the distribution features of the principal stress difference value under the influences of two mining as well as the plastic zone features of the gateway retained along the goaf under the different stress stage. The results showed that the principal stress difference value of the surrounding rock along the gateway retained along the goaf would have five stages under the influences of the first mining and the second mining and would have t he stage increased features. During the first mining period, the plastic zone of the roof in the surrounding rock along the gateway retained was increased from 1.2m to 2.1 m, the plastic zones in the sidewall of the coal wall and the coal pillar were increased from 0.5 m to 2.0 m and 1.5 m individually. After the influences of the second mining stress, the plastic zone would be expanded with asymmetric features, the plastic zone in the roof at the sidewall of the coal pillar would have many plastic failure s, the failure depth could be 3.0 m, the plastic failure of the two sidewalls would be in symmetry and the scope of the plastic failure could be 2.5 m. Finally, the related e nhanced support measures were provided. After the site application, the convergence between the roof and floor of the surrounding rock was reduced by 38%, the conv ergence between the two sidewalls was reduced by 36% and the stability of the surrounding rock along the gateway was kept.