动静载叠加作用下深部巷道围岩变形破坏数值模拟研究

Numerical analysis of deformation and failure characteristics of deep roadway surrounding rock under static-dynamic coupling stress

在深部煤矿开采中,巷道往往处于高地应力和强动力扰动的动静载叠加应力环境。由动静载叠加诱发的围岩严重变形破坏甚至灾变失稳现象屡见不鲜,严重威胁煤矿的安全高效开采。因此,对动静载叠加作用下巷道围岩变形破坏规律的研究具有非常重要的理论价值和工程意义。本文以数值模拟中非线性动力计算为手段,研究了不同初始应力场及不同动载条件对巷道围岩的影响,获得了动静载叠加作用下巷道围岩变形破坏规律。结果表明:水平应力、垂直应力及动力扰动都与巷道围岩塑性破坏呈正相关关系,其中动力扰动对其影响最为明显。在相同应力条件下,巷道顶板和两帮的变形量及塑性破坏范围始终大于底板。水平应力对巷道变形量的影响比垂直应力更加强烈。所以,对于高应力环境中的矿井需加强地应力测试,并在巷道设计时充分考虑巷道布置及开采顺序。对于受动力扰动强烈的巷道,要求支护构件(锚杆、锚索等)在受到一定动力扰动后仍能保持其有效性。这一研究结果有助于进一步了解动静载叠加作用下深部巷道围岩变形破坏规律,并可为相似地质条件下巷道支护设计及优化提供相应的指导。

In actual production,deep coal mine roadways are often under typical static-dynamic coupling stress(SDCS)conditions with high ground stress and strong dynamic disturbances.With the increasing number of disasters and accidents induced by SDCS conditions,the safe and efficient production of coal mines is seriously threatened.Therefore,it is of great practical significance to study the deformation and failure characteristics of the roadway surrounding rock under SDCS.In this paper,the effects of different in-situ stress fields and dynamic load conditions on the surrounding rock are studied by numerical simulations,and the deformation and failure characteristics are obtained.According to the simulation results,the horizontal stress,vertical stress and dynamic disturbance have a positive correlation with the plastic failure of the surrounding rock.Among these factors,the influence of the dynamic disturbance is the most substantial.Under the same stress conditions,the extents of deformation and plastic failure of the roof and ribs are always greater than those of the floor.The effect of horizontal stresses on the roadway deformation is more notable than that of vertical stresses.The results indicate that for the roadway under high-stress conditions,the in-situ stress test must be strengthened first.After determining the magnitude of the in-situ stress,the location of the roadway should be reasonably arranged in the design to optimize the mining sequence.For roadways that are strongly disturbed by dynamic loads,rock supports(rebar/cable bolts,steel set etc.)that are capable of maintaining their effectiveness without failure after certain dynamic loads are required.The results of this study contribute to understanding the characteristics of the roadway deformation and failure under SDCS,and can be used to provide a basis for the support design and optimization under similar geological and geotechnical circumstances.