岩体爆破近区临界损伤质点峰值震动速度的确定

质点峰值振动速度(PPV)是爆破开挖扰动的重要指标，研究确定岩体临界损伤PPV对爆破损伤控制具有重要意义。以溪洛渡水电站640 m高程马道下边坡岩体的爆破开挖为工程背景，依据岩体跨孔声波测试结果，采用基于LS-DYNA的二次开发技术对保留岩体的损伤演化过程进行了数值模拟，结合数值模拟结果研究了爆破近区PPV的分布特征及其与损伤程度的对应关系，结果表明PPV存在门槛值，当PPV大于该值时，岩体的损伤变量从零开始迅速增加至0.8左右，之后随着PPV的增大，损伤增长速度明显减慢，直至岩体完全损伤；分别基于岩体的损伤度、最大拉应力的PPV判据以及近区拉应力峰值与PPV的统计关系等3种方法确定岩体临界损伤PPV，从定量衡量损伤区范围看，常用的基于最大拉应力的PPV判据确定的临界损伤PPV偏小，而其余2种方法确定的临界损伤PPV相对精确。

Determination of critical damage PPV near the blast hole of rock-mass

Based on the blasting excavation for the berm at the elevation of 640 m on the high slope of Xiluodu hydropower station, the blasting induced damage zone were obtained through sonic wave test and numerical simulation. The relationship between PPV and damage scalarD was studied. If PPV is bigger than one certain value, the damage scalar D increased quickly to about 0.8, then the increased speed became slow. A method of determining critical damage PPV was put forward based on the damage degree and it was compared with the methods of statistics relationship between the maximum tensile stress and PPV and the PPV criterion based on the maximum tensile stress. Results demonstrate that the accuracy of methods based on the damage degree and statistic relationship between the maximum tensile stress and PPV is better than the result according to the maximum tensile stress.