Study on Blasting Relaxation Test and Stability Influence of Underground Powerhouse Rock Wall Beam
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摘要: 针对特殊地质构造下岩壁梁区域围岩开挖成型困难、岩壁梁稳定性难以评估等问题,在某工程岩壁梁区域开展了爆破试验及声波测试,研究岩梁区域的加固措施以及应力松弛圈深度,通过试验数据修正岩壁梁稳定性评估结果。结果表明,爆前各测点松弛圈平均深度为1.73 m,爆后各测点平均深度约2.51 m,对比各试验段结果,岩壁梁树脂锚杆预加固方案围岩成型效果较好。利用测试数据对围岩及结构面参数进行复核,修正数值模拟计算结果,计算得到未考虑应力松弛圈深度时岩壁吊车梁与岩壁结合面的抗滑稳定性安全系数为6.89,考虑应力松弛圈深度时,安全系数降至3.13,岩壁梁处于稳定状态。该岩壁梁爆破松弛试验方法及稳定性计算方法可为类似工程提供参考。Abstract: In view of the difficulty in forming the surrounding rock in the rock wall beam area under special geological structures, and the difficulty of assessing the stability of the rock wall beam, a blasting test and sonic test were carried out in the rock wall beam area of an engineering to study the reinforcement measures and stress in the rock beam area. The depth of the relaxation zone was used to modify the results of the stability evaluation of rock wall beams through experimental data modification. The results show that the average depth of the relaxation zone at each measuring point before blasting is 1.73 m, and the average depth of each measuring point after blasting is about 2.51 m. Comparing the results of each test section, the rock wall beam resin anchor pre-reinforcement scheme has a better surrounding rock forming effect. Use the test data to recheck the surrounding rock and structural surface parameters, and modify the numerical simulation calculation results. The safety factor of anti-sliding stability of the rock wall crane beam and the joint surface of the rock wall is 6.89 when the depth of the stress relaxation zone is not considered. When considering the depth of stress relaxation zone, the safety factor is reduced to 3.13, and the rock wall beam is in a stable state. The blasting relaxation test method and stability calculation method of rock wall beam can provide reference for similar projects.
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Key words:
- rock wall beam /
- blasting test /
- stress relaxation zone /
- stability analysis
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表 1 各试验段开展钻孔声波测试具体方案
项目 试验段 每孔
孔深
/m钻孔
孔径
/mm工作量
/m实施时间 岩梁爆破前
岩体声波造孔A、B 12 76 共24 Ⅱ层中间
拉槽结束C、D、E 9 76 共27 保护层
开挖结束岩梁爆破后
岩体声波
原孔位扫孔A、B、C、D、E 9 76 共90 岩梁试验段
爆破开挖后表 2 岩体物理力学参数取值表
围岩分类 密度ρ
/(g·cm−3)岩体变形
模量/GPa岩体弹性
模量/GPa泊松比ν 抗剪断(岩/岩) f ′ c′/MPa Ⅳ 2.1 2.5 3.5 0.32 0.57 0.35 Ⅴ 2.1 1 0.8 0.35 0.45 0.10 表 3 结构面物理力学参数
结构面类型 抗剪断强度 代表性结构面 f ′ c′/MPa 硬性结构面 0.54 0.15 节理 软弱结构面 岩块岩屑型 0.46 0.10 F12、f52 岩屑夹泥型 0.37 0.05 F10、F15、f34、f56 泥夹岩屑型 0.25 0.01 F2、F7、f50、f53、f55、f71 表 4 监测值与计算值相对误差统计表
监测仪器编号 测点深度/m 监测值/mm 未考虑应力松弛圈 考虑应力松弛圈 计算值/mm 相对误差/% 计算值/mm 相对误差/% Mcf-0-000-1 10 3.82 5.35 28.60 5.79 34.02 5 8.1 10.64 23.87 11.71 30.83 2 14.37 12.15 −18.27 14.96 3.94 0 19.26 17.55 −9.74 19.55 1.48 Mcf-0-000-4 10 3.15 4.00 21.15 4.86 35.23 5 5.73 8.08 29.08 9.84 41.75 2 12.78 10.32 −23.81 12.57 −1.70 0 17.35 13.49 −28.62 16.42 −5.65 Mcf-0-000-5 10 2.78 2.95 5.86 3.42 18.62 5 4.37 5.97 26.83 6.91 36.75 2 9.25 7.63 −21.24 8.83 −4.80 0 11.54 9.97 −15.74 11.53 −0.05 -
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