巷道变形差异化响应特征及支护设计分析

Differentiation response characteristic of roadway deformation and rock supporting analysis

巷道围岩变形响应特征的演化对其支护研究有着重要意义。首先基于弹性力学建立不同应力条件下考虑支护压力的圆形巷道力学模型,得到不同侧向应力系数(k)条件下巷道顶底板和两帮变形的差异化响应特征,且对差异化响应过程进行分析。基于此可以对巷道的支护提供如下的指导意义:①当k>1时,应重视巷道顶(底)板的支护;当k<1时,应重视巷道两帮的支护;②针对侧向临空巷道、超前支承应力影响范围内的巷道要重视两帮的支护,针对上覆采空区范围下的巷道要重视对于顶(底)板的支护;③一般情况下浅巷重顶(底),深巷重帮。最后以山西某矿152052巷道为研究对象,测量巷道围岩内部地应力信息,结合巷道围岩内部裂隙发育特征,提出采用“锚索+锚杆+钢筋托梁+金属网”对巷道顶板和两帮进行支护设计,且取得了良好的支护效果。

Deformation characteristic evolution of roadway surrounding rocks is important for roadway support applications.In this study,a mechanical model is established for circular roadway by considering the support pressure under different stress conditions,based on the elastic theory.Different response characteristics of roadway deformation are analyzed for different k(the ratio of vertical stress to horizontal stress).Based on the identified roadway deformation characteristics,it is suggested:①roof and floor should be reinforced when k>1,and sidewalls should be reinforced when k<1;②side walls should be reinforced for gob-side roadway and roadways under the front abutment pressures,while roof and floor should be reinforced for roadways under the mined area of the upper seam;③roof and floor should be reinforced for shallow roadways,whereas sidewalls should be reinforced for deep roadways.A frield trail was performed at the 152052 roadway of a mine in Shanxi;The horizontal(σ_(x))and vertical stresses(σz)of the studied roadway were measured.Based on the fracture development characteristics obtained by means of borehole televiwering,it was found that the sidewalls needed to be reinforced and a support scheme“bolt cable+bolt+supporting plate+metal mesh”was purposed for the roadway.