城市浅埋隧道采用钻爆法掘进,往往涉及下穿居民区。根据理论计算及现场调整参数,上台阶爆破采用先行预裂带和增设掏槽隔振空眼等手段,经过现场爆破振动测试,采用先行预裂带等手段可以使爆破振动速度降低到国家标准的50%以下。为保护居民与业主及施工单位的权益,综合考虑现场地质地貌及前人的结论,进行爆破振动测试时采用垂直于掘进方向布点,并通过最小二乘法反演得到萨道夫斯基公式中的K,α值,再根据所得参数及萨道夫斯基公式计算出影响距离,得出该地质条件下的振动影响距离为38m。
Tunneling of the urban shallow tunnels by the method of drilling and blasting often involves under passing residential areas. Based on the theoretical calculation and the parameters adjusted on-site,the blasting vibration velocity is decreased under 50% of the national standard,by applying the methods of presplit blasting for up stage blasting,adding vibration-isolated empty cut holes. In order to protect the benefit of residents,owners and the construction company,and given the geological and topographical features of the construction site,the test arrangement should be vertical to the tunneling direction when monitoring the blasting vibration. Meanwhile,the affected distance can be calculated by the measured parameters and Sodev's empirical formula,whose K value and α value is gained through the inversion of least square method. The result is 38 m.