深部巷道开挖应力演化特征分析

深部高地应力赋存条件下，巷道开挖使围岩的应力受到扰动而重新分布，围岩应力的 变化会导致岩体破坏和损伤，甚至造成巷道的整体失稳。为研究全断面法、台阶法2 种不同开挖 方法下，围岩掌子面轴心、顶底板、边墙、拱肩等关键点位的应力演化规律，依托某煤矿巷道， 运用FLAC3D软件进行数值模拟，定量分析了2种不同开挖方法下关键点位应力大小及应力方向的演 化特征。研究表明：对于2种开挖方法，开挖后各主应力大小趋于稳定时差别较小；对于参考面轴 心监测点，全断面法开挖时最小主应力旋转成平行巷道轴线方向，受下台阶的影响，台阶法开挖 最小主应力最终旋转成竖直方向；对于边墙、拱肩、拱顶、底板、底角等其他关键监测点，最终 的应力状态相差不大，但应力演化路径相差显著，破坏机理也不同；与全断面法开挖相比台阶法 开挖下巷道底板位置处塑性区体积明显偏小，下台阶对底板围岩具有一定的保护作用。深入研究 应力变化对围岩稳定的影响对理论和工程研究具有重要意义，为开展室内实验以及现场工业实验 提供依据。

Analysis of Stress Evolution Characteristics of Deep Roadway Excavation

Under the action of deep high ground stress,the stress of surrounding rock is disturbed and redistributed due to the excavation of roadway.The change of surrounding rock stress will lead to rock failure and damage.FLAC3D is used to conduct numerical simulation based on a roadway in order to study the stress evolution law of the critical points of surrounding rock face such as axis,vault,floor,wall and spandrel under two different excavation methods of the full-face method and the bench method.The evolution characteristics of stress magnitude and stress direction of critical points are quantitatively analyzed under two different excavation methods.The results show that there is little difference in the value when the principal stress tends to be stable after excavation by the two excavation methods;for the axis monitoring point of the reference plane,the minimum principal stress rotates into the direction parallel to the roadway axis during the full-section method excavation,the minimum principal stress of the lower method eventually rotate into the vertical direction for the impact of the bench method;the final stress state is not much different,but the evolution path of stress is significantly different and the failure mechanism is also different for other critical monitoring points such as wall,spandrel,vault,floor,and foot;the volume of the plastic zone at the roadway floor is obviously smaller under the bench excavation compared with the full-face excavation,the lower bench has a certain protective effect on the surrounding rock of the floor.It is of great significance to study the influence of stress change on the stability of surrounding rock in theory and engineering,and provide the basis for indoor experiment and field industrial experiment.