动力扰动下深部出矿巷道围岩的变形特征

Deformation Characteristics of the Surrounding Rock in Deep Mining Roadway Under Dynamic Disturbance

以冬瓜山铜矿井下900 m深处的出矿巷道作为研究对象,基于"隔一采一充一"阶段凿岩、分段崩落的回采方案,利用FLAC3D数值模拟软件研究了静动态开挖过程中出矿巷道围岩的变形特征。模拟相关岩体力学参数由三轴压缩及频繁冲击扰动试验数据折减获得,采用Mohr-Coulomb模型进行静态开挖分析,结合Strain-Softening模型进行动态扰动影响模拟分析。研究结果表明:爆破产生的扰动促使围岩变形加剧,但不会改变静态开挖时围岩变形演化的规律;开挖时巷道周边产生应力卸荷现象,且顶板出现拉应力,靠近采场巷道两帮应力离散性大,造成顶板易产生拉伸破坏,靠近采场巷道两帮易发生片帮;结合深部出矿巷道实际稳定情况,推测巷道顶板及靠近采场部位易产生破坏,需加强支护,其余部位稳定性相对较好。

When deep rock mass is in a complex geological and mechanical environment,factors such as high stress and blasting disturbance usually affect the stability of surrounding rock in deep roadway directly. At present,the research analysis to deformation characteristics of surrounding rock in deep mine roadway is still inadequate,especially the actual destruction of roadway surrounding rock. So it is significant to study deformation characteristics of surrounding rock under dynamic disturbance,which can provide theoretical reference for supporting deep roadway surrounding rock.Through the investigation and analysis of engineering geological conditions of Dongguashan copper mine and occurrence conditions of No.Ⅰ orebody,the study on deformation regularity of roadway surrounding rock under static and dynamic load was conducted,and the numerical model is established according to the mining scheme. Therefore,taking the mine roadway of Dongguashan copper mine in the downhole 900 m deep as the research object,FLAC3D numerical simulation software was used to analyze the deformation characteristics of surrounding rock in the mining roadway,which based on the stopping scheme of the stage drilling block caving about“one charge one by one”.At first,the static and dynamic mechanical parameters of marble,skarn,serpentine,siltstone were measured through the indoor rock mechanics test,then the static and dynamic parameters of rock mass were obtained based on the generalized hoek-brown criterion. That is also to say,the simulated mechanical parameters of rock mass were obtained by reduced triaxial compression and frequent impact perturbation test data.After the establishment of the numerical calculation model,the Mohr-Coulomb model was used for static excavation analysis,and the dynamic disturbance impact simulation analysis was carried out with the Strain-Softening model,both of them were used to analyze the stress evolution and displacement evolution in roof and floor of roadway as well as both sides of surrounding rock.At last,the accuracy of the numerical simulation results was analyzed based on the actual failure of surrounding rock in the deep excavation of Dongguashan copper mine.The results show that the static and dynamic softening parameters of deep rock mass are obtained by reduction,based on test data of triaxial compression and frequent disturbance,which can be used as the basic parameters of numerical simulation analysis. What’s more,stress unloading occurred around the roadway,tensile stress appeared on the roof,while the stress on the floor was relatively small.The stress dispersion of the roadway side near the stope is greater than other side, and the change trend of stress isn’t obvious during dynamic disturbance.With the proceeding of excavation,the displacement increment of the roadway roof and the side roadway near the stope is larger than the side roadway deviated from the stope.At the same time,the roadway floor appears stable period,that is,the displacement does not change.Combined with the actual failure situation of surrounding rock in deep mining roadway,it can be speculated that roadway roof and the side roadway near the stope are prone to damage.As a result,the support should be strengthened and the rest parts are relatively stable.