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对溪洛渡水电站左岸出线竖井开挖爆破的振动速度进行了现场测试。运用萨道夫斯基公式对测试数据进行回归分析,得到了竖井爆破掘进中地震波传播衰减公式。利用该式预测距离井底高程差为18.2～24.5m处范围内测点的振动速度,并与实测数据进行对比。结果显示,竖井爆破振动的传播存在高程放大效应,水平振速放大系数约为1.49～2.24,垂直振速放大系数约为1.78～2.73;通过考虑高程效应对萨道夫斯基公式进行了修正,得到考虑高程因子的衰减公式,线性关系显著,对存在高程放大效应的爆破振动预测具有借鉴意义。运用动力有限元分析方法对竖井结构在爆炸冲击波荷载作用下的结构响应进行数值模拟,数值模拟结果与现场测试结果的对比表明,当相对高差不大时,两者整体趋势比较吻合,距离井底0～15m,振动速度快速衰减,振动速度峰值衰减幅度超过总体幅度的60%;距离井底超过30m,衰减不超过总幅度的10%。采用岩石-混凝土强度破坏准则对竖井构筑物在爆炸冲击荷载作用下的稳定性进行了强度校核,为竖井后续施工安全提供了参考。
Field tests were carried out on the vibration velocity of excavation blasting on the left bank of Xiluodu hydropower station. The regression analysis of the test data by using the Sadowssky formula gives the formula of seismic wave propagation attenuation in shaft blasting. This method is used to predict the vibration velocity of measuring point within the range of 18.2 ~ 24.5m from the bottom hole height, and compared with the measured data. The results show that there exists vertical amplification effect of shaft vibration, the horizontal vibration amplification coefficient is about 1.49-2.24, and the vertical vibration amplification coefficient is about 1.78-2.73. By revising the Sadowssky equation by considering the elevation effect, Taking into account the attenuation formula of elevation factor, the linear relationship is significant, which is of reference for the prediction of blasting vibration with elevation effect. The dynamic response of the shaft structure under blast shock wave loads is simulated by dynamic finite element method. The comparison between the numerical simulation results and the field test results shows that when the relative height difference is not large, the overall trend of the two is in good agreement. At the end of 0 ~ 15m, the vibration velocity decays rapidly, and the peak attenuation amplitude of vibration velocity exceeds 60% of the overall amplitude; the distance from the bottom of the well exceeds 30m and the attenuation does not exceed 10% of the total amplitude. The strength of shaft structure under blast impact load was checked by using the criterion of rock-concrete strength failure, which provided reference for the subsequent construction safety of shaft.