“铁篦子”方案在岩爆区的应用
Application of the ‘iron grate’ program in the area of rock burst

摘要： 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。
Abstract: To reduce the scale of rockburst control, the “iron grate” or “steel bar” scheme was analysed in this paper. The kinetic energy of different rockburst grades was calculated by using the elastic energy density of the surrounding rock mass after tunnel excavation. Based on the back analysis results of NJ-TBM tunnel ground stress and the stress release hole adopting in the engineering area, the maximum rock mass and the maximum velocity of different rockburst zones were determined. A “iron bar or bar row” solution was established by assuming that the maximum rock mass was impacted at the maximum speed to the steel plate / steel bar.Based on the model, the proposed scheme was applied to the strong rockburst, medium rockburst and weak rockburst respectively. The results showed that the program of steel arch spacing 1.5 m and the number of “iron grate”(Φ=20 mm)was 30 at each extension in the strong rockburst area hasnt appeared plastic area. The program of steel arch spacing 1.7 m and the number of “iron grate”(Φ=22 mm)was 20 at each extension in Medium rockburst area, the program of steel arch spacing 2.0 m and the number of “iron grate”(Φ=20 mm)was 20 at each extension in weak rockburst area hasnt appeared plastic area.So the proposed scheme wasnt produced plastic zone in the rockburst area