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膨胀软岩巷道围岩黏土矿物含量高、自身强度低、亲水膨胀性强,在复杂地应力和水理作用下极易发生变形失稳。结合小屯矿轨道大巷支护变更工程实践,通过地质调查、现场观测及室内试验等手段分析发现:巷道渗水量大,围岩节理裂隙发育、孔隙率高,膨胀性黏土含量高,水化作用后耐崩解性差都加剧了围岩的变形失稳。针对性地提出以格栅钢架为主体结构的“全封闭格栅钢架+挂网+锚杆+喷射/浇筑混凝土”联合支护体系,通过数值模拟,揭示了全封闭支护设计的整体性优势,并对支护方案的格栅钢架间距和锚杆长度进行优化,制定出适用现场工况的钢架规格参数及其施工工艺流程。同时辅以集水坑降低底板水位,最终以全封闭格栅钢架为主体结构的联合支护体系有效地控制了巷道围岩变形,在小屯煤矿膨胀软岩巷道取得了成功应用。
Expansive soft rock roadway surrounding rock clay mineral content is high, its own strength is low, hydrophilic swelling strong in the complex under the action of stress and water prone to deformation instability. Combined with the engineering practice of the support alteration in the roadway of Xiaotun Mine, it is found through geological survey, field observation and laboratory test that the seepage volume of the roadway is large, the fractured rock of the surrounding rock is developed, the porosity is high, the content of the swelling clay is high, After the role of poor resistance to disintegration have aggravated the deformation of the surrounding rock instability. This paper proposes a combined support system of “fully enclosed lattice steel frame + netting + anchor + spray / pouring concrete” with the grid steel as the main structure. The numerical simulation shows that the fully enclosed support design The overall advantages of the support program and optimize the grille steel spacing and anchor length to develop a site for the conditions of the steel frame specifications and construction process. At the same time, the water collecting pit is used to reduce the water level of the floor, and finally the joint support system with the fully enclosed grid steel frame as the main structure effectively controls the deformation of the surrounding rock of the roadway. The soft rock tunnel has been successfully applied in the expansion of the Xiaotun coal mine.