分岔隧道安全高效施工方法优化研究

为降低分岔隧道大跨、超小净距段施工安全风险,满足进度需求，结合某市政公路分岔隧道施工实例，针对隧道地质条件差、周边环境复杂和敏感度高等特点，采取将小净距段替换中间岩柱由双连拱形式优化为单侧隧道扩挖并喷混凝土回灌的方法；分岔大跨段将左右两侧导坑加大，与原有2车道断面相似，中间导坑依次减小，两侧导坑可连贯施工优化为一体化双侧壁导坑法施工，实现对大跨、超小净距段施工方法的优化，有效地控制了施工风险，并实现了快速施工。

Optimization of Safe and Efficient Construction Method for Bifurcated Tunnel

To reduce the safety risk of the large span section and the ultra small clear distance section of the bifurcated tunnel, and to meet the schedule requirements, the method of replacing the middle rock pillar by small clear span section and the optimizing the double arch to side tunnel and enlargement and shotcrete is adopted according to the bad tunnel geological conditions, complex surrounding environment and high sensitivity of a bifurcated municipal tunnel. And then the side pilots of bifurcated large span section are enlarged to original size of 2 lane cross section, the middle pilot is reduced in sequence, and the coherent construction of the pilots on both sides can be optimized into the integrated double side piloting method. By adopting the method mentioned above, the optimization of the construction method of the long span section and the ultra small clear distance section can be realized, the construction risk can be effectively controlled, and rapid construction can be achieved.