城区单薄山体岩石高边坡爆破振动高程效应研究

Altitude effect of blasting vibration on high rock slope belonging to thin mountain in urban area

为了探明几何形态特殊的单薄山体岩石高边坡的爆破振动响应特征,在赤湾停车场场平石方开挖爆破过程中,开展了赤湾山单薄山体岩石高边坡爆破振动监测,分析了赤湾山岩石高边坡爆破振动PPV和主频的分布规律,拟合了赤湾山岩石高边坡爆破振动PPV和主频的预测公式,分析了赤湾山岩石高边坡爆破振动的高程效应。结果表明:赤湾山单薄山体岩石高边坡马道内侧爆破振动PPV随水平爆心距和相对高差增大呈现先衰减后增大的趋势,在一定高程以上爆破振动PPV呈现明显的高程放大效应,坡顶监测点PPV约为坡脚的3~8倍;爆破振动主频随水平爆心距和相对高差增大呈先衰减后波动稳定的趋势,在一定高程以上爆破振动主频稳定在25 Hz左右。赤湾山岩石高边坡爆破振动高程效应与单薄山体岩石高边坡形态有关,雄厚山体岩石高边坡爆破振动PPV和主频公式对单薄山体岩石高边坡爆破振动PPV和主频的拟合效果一般。

To examine blasting vibration characteristics of high and thin rock slopes with a special geometry,the blasting vibration monitoring on the high and thin rock slope belonging to Chiwan Mountain was conducted during field leveling of Chiwan parking lot.The distribution laws of PPV and dominant frequency were then investigated,the formulae for predicting PPV and dominant frequency were fitted,and the altitude effect of blasting vibration was clarified.The results show that the PPV at the inner berm side of the thin and high rock slope first decays and then rises with the increasing horizontal distance from blasting source and the relative altitude difference,and there is an evident altitude amplification effect above a certain altitude.The PPV at the slope top is about 3 to 8 times of that at the slope toe.The dominant frequency first decays and then fluctuates with the increasing horizontal distance and the relative altitude difference,and the dominant frequency keeps about 25 Hz above a certain altitude.The altitude effect of blasting vibration on the thin and high rock slope is related to the topography of the thin and high rock slope,and it is hardly represented by the relevant PPV and dominant frequency formulae for the thick and high rock slope.