Calculation of P wave quality factor of rock mass based on measured blasting vibrations
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摘要: 爆破地震波传播衰减研究对爆破振动预测及安全控制有着重要的指导意义。针对爆破振动实测信号,结合P波、S波的初至识别结果,计算P波、S波在岩体中的传播速度及P波的上升时间,进一步得出岩体介质P波品质因子。结合现场实测振动数据,计算丰宁抽水蓄能电站及舟山绿色石化基地试验区域内岩体介质P波品质因子,计算结果分别为19.02和14.07。结果表明,通过实测地表爆破振动计算得到的P波品质因子远小于经验公式的计算值及一般原岩的品质因子,说明地表疏松层对爆破地震波的传播衰减有较大影响。Abstract: Studies on the attenuating characteristic of blasting seismic waves in propagating process are important in prediction and control of blasting vibration effects by engineering blasting. Field blasting tests of single-hole were conducted to study the quality factor of rock mass. The wave propagation velocities and the pulse rise times can be obtained by using the first arrival of P wave and S wave. Finally, based on the rise time method, the P wave quality factor of rock mass can be calculated. By analyzing the measured blasting vibration signals in Fengning hydropower station and Zhoushan large petrochemical industry, the average P wave quality factors in the above two regions are found to be 19.02 and 14.07, respectively. The experimental results show that the values derived by measuring blasting vibrations are far less than the values predicted by the empirical formulas and measured by the original rock mass. This results indicate that the soft covering layer has great influence on the seismic waves propagation induced by blasting.
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Key words:
- blast field tests /
- blasting vibration /
- propagation velocity /
- pulse rise time /
- quality factor
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表 1 竖直钻孔爆破实验参数表
Table 1. Parameters of blasting design of the field experiment
炮孔 起爆位置 孔径/mm 孔深/cm 药卷直径/mm 装药长度/cm 堵塞长度/cm 单响药量/kg 1 上、底部 76 800 50 600 200 12.0 2 底部 76 800 50 600 200 12.0 3 中部 76 600 50 420 180 8.4 4 底部 76 600 50 420 180 8.4 5 中部 76 450 50 270 180 5.4 6 底部 76 450 50 270 180 5.4 表 2 实测振动波形P波初至识别结果
Table 2. P wave first arrivals identification results
炮孔 P波初至震相到时/ms 1# 2# 3# 4# 5# 6# 1 429.25 −0.38 −0.63 −0.63 −1.25 −8.25 2 897.13 467.50 467.00 467.13 466.50 459.13 3 1 531.50 1 101.88 1 101.13 1 101.13 1 100.25 1 093.25 4 1 628.75 1 199.13 1 198.38 1 198.50 1 197.00 1 190.63 5 2 583.13 2 153.50 2 153.00 2 153.13 2 153.13 2 145.00 6 3 053.00 2 623.25 2 622.63 2 622.75 2 621.13 2 614.75 表 3 实测振动波形S波初至识别结果
Table 3. S wave first arrivals identification results
炮孔 S波初至震相到时/ms 1# 2# 3# 4# 5# 6# 1 431.63 3.25 5.50 8.75 12.13 11.25 2 899.50 471.13 473.13 476.50 479.88 478.63 3 1 533.63 1 105.13 1 107.00 1 110.25 1 113.38 1 112.50 4 1 630.88 1 202.50 1 204.25 1 207.50 1 210.13 1 209.88 5 2 585.00 2 156.50 2 158.50 2 161.88 2 164.00 2 164.13 6 3 054.88 2 626.38 2 628.25 2 631.63 2 634.00 2 633.75 表 4 各测点上升时间计算结果
Table 4. Calculating results of rise time for various monitoring points
炮孔 3#测点 4#测点 5#测点 6#测点 $\tau $/ms vmax/(cm·s−1) $\tau $/ms vmax/(cm·s−1) $\tau $/ms vmax/(cm·s−1) $\tau $/ms vmax/(cm·s−1) 2 0.55 2.51 0.59 1.30 0.83 0.75 1.18 0.23 4 0.53 2.20 0.64 1.05 0.75 0.60 1.08 0.16 6 0.80 1.24 0.64 0.58 0.79 0.34 1.09 0.09 表 5 实测振动波形P波、S波初至识别结果
Table 5. Identification results of P and S wave first arrivals
测点 爆心距/m 初至时间/ms P波 S波 6# 23.6 18.90 22.67 8# 40.0 18.70 25.11 9# 54.6 18.70 27.44 12# 160.9 18.90 44.65 13# 225.6 18.60 54.71 表 6 各测点上升时间计算结果
Table 6. Calculating results of rise times for various monitoring points
测点 $\tau $/ms vmax/(cm·s−1) 6# 1.54 7.18 8# 1.65 2.63 9# 1.70 1.32 12# 2.61 0.30 13# 2.50 0.19 -
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