新建隧道下穿既有重载隧道施工控制技术研究

Research on Construction Control Technology of New Tunnel Under Existing Heavy Load Tunnel

为解决新建隧道下穿既有重载隧道工程,新建隧道的安全施工及既有隧道的安全运营问题,展开对下穿段主要施工技术及监控量测的研究。通过交叉隧道现场实测数据的反馈,合理优化隧道交叉段的支护参数;加强超前小导管及超前大管棚对前方围岩的预加固,对于交叉段Ⅳ级围岩采用Ⅴ级加强的初期支护形式;同时对交叉段DK173+954.4~DK174+970.9严格控爆,控制最大单响药量,设置大孔径空孔尽可能减小爆破施工对既有线路的振动损害。对既有隧道及新建隧道结构变形及爆破振动实时监测,实时改进隧道施工方案及支护措施。

In order to solve the problems of the safety construction of the new tunnel and the safe operation of the existing tunnel,the main construction technology and monitoring measurement of the underpass section are studied.Through the feedback of the field measured data of the cross tunnel,the supporting parameters of the cross section of the tunnel are optimized reasonably;the pre-reinforcement of the surrounding rock in front of the small pipe and the large pipe shed in advance is strengthened,and the primary support form of grade V is adopted for the grade IV surrounding rock of the cross section;At the same time,the blasting of dk173+954.4~dk174+970.9 at the intersection section is strictly controlled,the maximum single sound charge quantity is controlled,and large diameter empty holes are set up to minimize the vibration damage of the existing line caused by blasting construction.The real-time monitoring of structural deformation and blasting vibration of existing tunnel and new tunnel can improve the tunnel construction scheme and support measures in real time.