小净距隧道爆破控制措施及响应特征研究

Study on Blasting Control Measures and Response Characteristics of Small Clearance Tunnel

以厦门第二西通道海沧海底隧道为工程背景,为减小施工过程中小净距隧道后行洞爆破施工对先行洞的影响,制定了相应的施工方案与开挖方法,并计算了爆破参数。设计完成后首次爆破施工过程中发现爆破振动速度不满足要求,随后采取了一系列控制措施,优化后各测点爆破振动速度均满足要求。并对随后爆破施工过程中拱顶沉降、周边收敛、地表沉降进行了监测,结果表明:拱顶沉降与周边收敛的最大值均小于设计允许值,地表沉降在隧道正上方所监测值最大,其中由于左线隧道先于右线隧道开挖,因此左线隧道正上方累计沉降值最大。说明所采用的控制措施是合理的,可为类似工程提供参考。

Haicang subsea tunnel of Second West Passage in Xiamen is taken as the engineering background. The corresponding construction scheme and excavation method are formulated and the blasting parameters are calculated in order to reduce the influence of the blasting of the back tunnel of the small clearance tunnel on the front tunnel during the construction process. After the completion of the design, it was found that the blasting vibration velocity did not meet the requirements during the first blasting construction. And then, a series of control measures were applied to optimize the blasting vibration velocity of each measuring point to meet the requirements. The vault settlement, peripheral convergence and ground settlement during the subsequent blasting construction were monitored.The results show that both the maximum values of vault settlement and perimeter convergence are less than the designed allowable values. The maximum value of ground settlement is observed directly above the tunnel, and the maximum value is observed on the left because the left line was excavated before the right line. It shows that the control measures adopted are reasonable and can provide reference for similar projects.