基于偏应力场的巷道围岩破坏特征及工程稳定性控制

摘要

Aiming at the failure mechanism and stability control of roadway surrounding rock,based on rock mechanics and other related theories,the analytical solution of the deviatoric stress field of surrounding rock is deduced,the distribution of surrounding rock under different conditions is analyzed,and the constitutive equation of the deviatoric stress field and the plastic zone distribution is established.It shows that the radius of plastic zone is related to the angle of polar coordinates and the size of deviatoric stress,and can be an irregular distribution.Combined with engineering practice,numerical simulation and analysis are used to simulate and analyze the evolution process of deviatoric stress and plastic zone in the surrounding rock under different stress states when the vertical stress is larger than the horizontal stress (λ =0.4) and the horizontal stress is greater than the vertical stress (λ =1.6).According to the field investigation and the evolution characteristics of the plastic zone,the authors put forward that at different lateral pressure coefficients the roadway will form a typical pattern symmetric instable and a typical angular symmetric instability mode,also,the authors analyze the misunderstanding area with these two failure modes of roadway support,and the corresponding control principle and key technologies.Combined with the engineering practice of the Mukong coal mine and Gaokeng Coal Mine," Bolt+Cable" support is applied to the main support named "high strength rigid truss" integrated support technology to help improve the stability of the sizes.In addition,the "key parts grouting" is used to enable the inside and outside coupling of "Bolt +U-steel + Cable" comprehensive treatment program.The application shows that the two are able to control alternative symmetric instable roadway and angular symmetric instability roadway.%针对巷道围岩破坏机理及稳定性控制问题,采用岩石力学等相关理论推导了巷道围岩偏应力场的解析解,分析了圆形巷道围岩在不同情况下的分布情况,建立了偏应力场与塑性区分布的本构方程,表明塑性区半径与极坐标的角度和偏应力是密切相关的,可呈不规则分布;结合工程实际,采用数值计算模拟分析了垂直应力大于水平应力时(侧压系数λ=0.4)和水平应力大于垂直应力时(侧压系数λ=1.6)不同应力状态下的巷道围岩偏应力和塑性区演化过程;根据现场调查及塑性区演化特征,提出在不同侧压系数下巷道围岩可形成典型正对称失稳模式和典型角对称失稳模式,并分析了这两种破坏模式的巷道围岩支护误区,以及相应的控制原则与关键技术.结合木孔煤矿和高坑煤矿的工程实践,应用了以“锚杆+锚索”支护为主,以提高两帮稳定性目标的“高强刚桁架”综合支护技术;以及以“关键部位注浆”,发挥内、外耦合作用的“锚杆+U型钢+锚索”综合治理方案.工程实践表明,所提出的支护方案分别能对正对称失稳巷道和角对称失稳巷道围岩变形能起到较好的控制效果.