单薄山体岩质高边坡爆破振动响应分析及安全控制

Blasting vibration response and control of high rock slopes of thin mountain

针对赤湾山高边坡爆破振动响应问题,开展了爆破振动实测数据分析和动力有限元数值模拟,分析了单薄山体岩质高边坡的爆破振动响应特征。结果表明:幅值方面,迎爆侧坡面存在明显的爆破振动高程放大效应,高程放大效应测点的主振方向偏于垂直坡面走向;背爆侧坡面爆破振动随爆心距增加整体呈衰减趋势。持续时间方面,迎爆侧坡面爆破振动完整波形持续时间和优势振动持续时间均随水平爆心距和高程增加而显著延长;坡顶附近,测点起振时刻越晚,其爆破振动峰值反而越大。频率方面,赤湾山边坡自振频率远大于常见单面边坡的自振频率;随水平爆心距和高程增加,迎爆侧坡面爆破振动视主频整体呈衰减趋势,优势频带由100 Hz左右衰减至15 Hz左右,且落在边坡固有频率内。结合赤湾山高边坡爆破振动响应特征和工程实际,采取电子雷管起爆网路、优化开挖程序和抵抗线方向、边坡支护防护等措施控制爆破振动。

The blasting vibration response characteristics of high rock slopes of a thin mountain are studied by analyzing the monitoring data and numerical results of blasting vibration of Chiwan Mountain high rock slope. The results in vibration amplitude show that the elevation amplification effect of blasting vibration exits on the south slope, and main vibration directions of the monitoring points showing elevation amplification effect are across the slope. However, the blasting vibration decays versus distance on the north slope. In terms of vibration duration, durations of complete blasting vibration and dominant vibration waveforms on the south slope are significantly prolonged with the increase in distance from the blasting source to the monitoring points. Near the top of the slope, the later the starting point of blasting vibration is, the larger the particle peak velocity of the blasting vibration is. In terms of frequency characteristics, the natural frequency of Chiwan Mountain high rock slope is much higher than that of the common single-sided rock slope. With the increase of the distance from the blasting source to the monitoring points, apparent frequency of blasting vibration on the south slope decreases, and the dominant frequency band of blasting vibration is reduced from high frequency band around 100 Hz to the low one around 15 Hz that falls within the natural frequency range of the slope. Finally, three measures, including electronic detonator initiation network, excavation procedure and resistance line direction optimization, and support and protection, are proposed for controlling the blasting vibration of Chiwan Mountain high rock slope.