预裂爆破震动效应试验研究

EXPERIMENTAL STUDY OF VIBRATION EFFECT OF PRESPLIT BLASTING

为研究预裂爆破震动效应,在山东石岛湾核电站基坑进行多次爆破和声波测试试验,得到场地爆破震动衰减规律和爆孔下卧基岩的损伤范围。试验结果表明,岩性相同时,基岩损伤深度随最大段药量的增加而线性增加,随质点峰值震动速度增加而呈指数增加;离爆源越近,岩体受损程度越大;预裂爆破对爆孔上部岩体影响较大。同时,在试验的基础上,建立距爆源30 m处质点峰值震动速度与对应爆破影响下卧基岩深度的函数关系,进而确定以质点峰值震动速度为参考指标的预裂爆破安全控制标准,并在基坑边坡爆破中验证该控制标准的有效性。

In order to study the vibration effect of presplit blasting,blasting vibration and sound wave tests are conducted in the foundation pit of Shidao Bay Nuclear Power Station in Shandong Province,China.Based on the change rate of sound wave velocity before and after blasting,damage depth of bedrock is determined.The attenuation law of site blasting vibration is obtained through in-situ test.The test results indicate that,under the same lithology the bedrock damage depth increases linearly with maximum charge weight per delay interval,and increases exponentially with the increase in peak particle vibration velocity.The degree of rock mass damage increases with the reduction in distance from explosion source.Presplit blasting mainly affects the upper part of rock mass.Furthermore,based on field test,the relationship between damage depth of bedrock caused by blasting and peak particle vibration velocity of rock mass 30 m away from explosion source is established;and peak particle vibration velocity is adopted as the reference parameter to be the safety control standard of presplit blasting excavation.It is shown that the controlling method effectively ensures safety of rock mass under presplit blasting excavation in foundation pit slope.