频繁爆破条件下既有隧道支护结构动态响应研究

以邻近既有隧道的保和村隧道为依托,研究在新建隧道推进式、往复、频繁爆破开挖过程中邻近既有隧道支护结构的动态响应特征。爆破振动速度监测结果表明,邻近既有隧道迎爆侧的拱肩到拱腰部位振动最为强烈,应严格控制振动速度;围岩声波波速监测结果表明,既有隧道支护结构在一定程度上发生损伤、破坏,尤其是迎爆侧。基于对监测结果的分析和损伤效应,对爆炸荷载进行分析简化;结合现场振动监测对爆轰压力进行修正,计算衬砌的振动速度和拉应力,实现动态响应数值模拟;通过数值计算,达到优化装药量以控制邻近既有隧道动态响应特征的目的。

Study on Dynamical Response of Supporting Structure of Existing Tunnels Under Frequent Blasting

Based on the Baohe Village Tunnel adjacent to the existing tunnel,this paper investigates the dynamic response characteristics of the existing tunnel’s supporting structure in response to the advancing,reciprocating,and frequent blasting and excavation activities of an adjacent,newly-built tunnel.Results obtained from the blasting vibration velocity monitoring show that the vibration is the strongest from the arch shoulder to the arch waist of the existing tunnel,and the vibration velocity should be strictly controlled;results from the surrounding rock acoustic wave velocity monitoring show that the supporting structure of the existing tunnel has undergone damage and destruction to a certain extent,especially on the side directly facing the blasting.Based on the analysis of the monitoring results and the damage effect,the explosion load is analyzed and simplified;the on-site vibration monitoring is used to correct the detonation pressure,and the vibration velocity and tensile stress of the lining are calculated to assist with the numerical simulation of the dynamic response;through the numerical calculation,the purpose of controlling the dynamic response characteristics of adjacent existing tunnel is realized by optimizing explosive amount.