层状岩体中近邻双线隧道爆破的振动响应研究

Study on Blasting Seismic Dynamic Effect for Tunnels with Close Interval in Bedded Rock Mass

近邻双线隧道爆破开挖时,为了避免新建隧道爆破施工产生的地震波危及既有隧道的安全和稳定,基于数值模拟和现场试验,分析了层状岩体中采用钻爆法修建近距离双线隧道的爆破振动响应.结果分析表明,对于既有隧道,迎爆面侧墙处的振动速度和反射拉应力最大,而且振动速度具有很强的方向效应,隧道径向振动速度大于切向振动速度,其规律与现场爆破试验结果有较好的一致性.将爆破对新建隧道本身围岩的振动损伤度和对相邻隧道的振动影响结合起来综合考虑,提出了层状岩体隧道爆破施工中减轻振动的几种措施,并对隧道爆破参数进行了优化.图7,表4,参8.

The influence of blasting vibration from the excavation of new tunnel on the adjacent existed tunnel in nature is a blasting optimizing question, which key is to find the method of reducing the blasting vibration. In order to insure the safety and stability of existed tunnel, the blasting dynamic effect in double line tunnels constructed in stratified rock mass is analyzed based on the numerical simulation and site blasting test. Result shows that the maximum vibration speed and reflecting tensile stress occur on tunnel wall and arch section facing the blasting side, and the velocities decrease nonlinearly along with the increase of distance away from the explosion source. The vibration velocities have distinct directional effect, and the radial velocities are much greater than those in tangential direction. Radial vibration velocities have the controlling effects on the damage of rock mass of existed tunnels. Finally, the explosion parameters are optimized by the comprehensive consideration of vibration damage induced by explosion and its influence on existed tunnel, and measures for reducing the blasting vibration are proposed.Trigs., 4tabs., 8refs.