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为减少岩爆控制的规模,采用“铁篦子或钢筋排”方案对其进行研究。利用隧道开挖后周围岩体的弹性能密度计算不同岩爆等级发生时的动能;根据前期对NJ—TBM隧洞地应力的反分析成果,结合工程区域采取应力释放孔等措施,确定不同岩爆区的最大岩块及其最大速度,且假定最大岩块以最大速度向钢板/钢筋进行冲击,从而建立“铁篦子或钢筋排”方案计算模型;基于该模型,将所提出的“铁篦子或钢筋排”方案分别应用到强岩爆区、中等岩爆区以及弱岩爆区。结果表明:在强岩爆区(钢拱架间距1.5 m,每延米30根Φ=20 mm“铁篦子”的方案)中岩爆区(钢拱架间距1.7 m,每延米20根Φ=22 mm“铁篦子”的方案)弱岩爆区(钢拱架间距2.0 m,每延米20根Φ=20 mm“铁篦子”的方案)均未使钢筋出现塑性区。因此,所提出的方案不会产生塑性区。
In order to reduce the size of the rock burst control, the “iron grate or steel bar” scheme was used to study it. The kinetic energy of different rockburst levels is calculated by the elastic energy density of surrounding rock mass after tunnel excavation. According to the results of back analysis on the ground stress of NJ-TBM tunnel and the stress release holes in the project area, the rock burst The maximum rock mass and its maximum velocity in the area and assuming that the maximum rock mass strikes the steel plate / rebar at the maximum velocity to establish the calculation model of “iron grate or rebar”; based on this model, the proposed “ Iron grate or steel bar ”program were applied to the strong rock burst zone, medium rock burst zone and weak rock burst zone. The results show that in the area of strong rockburst (the distance between steel arches is 1.5 m, the plan of 30 Φ = 20 mm / “iron grate” per meter) Weak rock burst zone (2.0 m spacing of steel arches, 20 per Φ = 20 mm “iron grate” scheme) did not make the rebar plastic Area. Therefore, the proposed solution does not produce plastic zone.