拱北隧道5台阶14部开挖施工组织方案分析

Analysis of Construction Organization Scheme of Five-bench Fourteen-step Excavation Applied to Gongbei Tunnel

港珠澳大桥拱北隧道口岸暗挖段采用255 m曲线管幕+冻结法施工,采用5台阶14部开挖方法穿越富水软弱地层及拱北口岸敏感区域。为解决该工法下大断面开挖及多工序交叉作业施工的施工组织及安全问题,从现场管理角度出发介绍5台阶14部开挖法的施工方案,通过现场施工验证方案的可行性,并分析施工中存在的部分台阶断面划分、导洞施工顺序安排、工作面设置等方面存在的问题。据此,提出开挖方案和施工组织优化思路以及增设斜坡道的比选方案,监测结果表明:施工组织调整及优化是切实可行的,能够确保拱北隧道按期顺利贯通。

The 255 m-long mined section of Gongbei Tunnel of Hong Kong-Zhuhai-Macao Bridge, crosses water-rich weak stratum and sensitive area of Gongbei Port, is constructed by curved pipe roof + freezing method and five-bench and fourteen-step excavation method. In order to guarantee the smooth construction organization and construction safety, the detail of five-bench and fourteen-step excavation method is introduced from the perspective of site management;the feasibility of the scheme is verified by field construction;and the existing problems, such as cross-section division of some benches, construction sequence arrangement of pilot tunnel, working face arrangement, etc., are put forward. Finally, the idea of excavation scheme and construction organization optimization and the comparison and selection scheme of adding ramp are proposed, and the monitoring results show that: The construction organization adjustment and optimization are feasible, which can ensure the smooth completion of Gongbei Tunnel on schedule.