小间距隧道爆破对既有隧道振动影响分析

摘要

以实际工程为依托,分析爆破振动对临近既有隧道的影响.施工前对既有隧道进行结构病害检测并评估其安全状况,施工过程中对既有隧道爆破振动速度进行现场监测,以确保爆破施工过程中既有隧道的结构安全.对现场监测结果进行统计和回归分析,确定了爆心距以及分段装药量对于爆破振速传播规律影响,将爆破振动对既有隧道衬砌的影响根据爆破振动速度分为无影响、微影响、较大影响和安全性影响4个等级.针对于小净距隧道工程特点,提出爆破安全控制技术措施及处治建议,包括合理开挖工法的选择、分段装药量的确定及掏槽形式的选择等.%The effect of blasting vibration on neighboring tunnel was analyzed based on the actual project.The damage test and safety evaluation for the existing tunnel liner structure was conducted before tunnel construction.Blasting vibration monitoring of the old tunnel was also carried out to ensure the safety of tunnel structure.With the method of statistical and regressive analysis of monitoring data,the influence law of distance to blast source and charge amount per delay to the blasting vibration were determined.Four grades of the effect on existing structure were classified as no effect,slightly effect,big effect and hazardous effect.Some control measures and suggestions were presented to ensure the blasting safety for the small spacing tunnel,including reasonable excavation method,determination of explosive charge and cutting mode.