大断面巷道煤柱帮在开挖扰动下的应力场

Stress Field of Coal Pillar in Large Section Roadway under Excavation Disturbance

针对施工时大断面巷道煤柱帮易发生片帮的现状,为探索帮体失稳的力学机制,基于弹性力学理论,分析垂直静压环境下煤柱帮受水平开挖扰动时的应力场分布规律,得到煤帮的应力解析表达式,结果显示应力特征由开挖振速、垂直地应力、煤柱几何尺寸以及煤体内应力波波速等因素共同决定。结合具体算例发现帮最大水平应力、最大剪应力及最大垂直应力分别分布于帮表面、帮底角和帮顶角。在此基础上,引入岩体破坏准则,获得了使煤柱帮保持稳定的最大开挖振速表达式,据此得出帮上部岩体是最易因开挖扰动而出现破坏的结论。

In the light of the present situation about the wall caving of coal pillar with large section roadway constructing,in order to explore the mechanical mechanism of the instability of the coal pillar,based on the elastic mechanics theory,the stress field distribution law of the coal pillar was analyzed under the vertical static pressure and the horizontal excavation dynamic pressure,and the analytical expression of the stress was obtained.The results show that the stress characteristics were driven by the excavation vibration speed,vertical stress,coal pillar geometry and stress wave velocity in coal body.It was found that the maximum horizontal stress,maximum shear stress and maximum vertical stress were distributed on the coal pillar surface,the bottom angle and the top angle respectively.On this basis,the failure criterion of rock mass was introduced,and the expression of maximum excavation vibration speed was obtained.