西宁至成都铁路甘青隧道TBM施工方案研究

根据甘青隧道"海拔高、地质条件复杂、生态环境脆弱、辅助坑道设置条件差"等特点,分析钻爆法施工存在的技术问题,并开展TBM施工可行性研究。基于地勘资料,逐段分析TBM施工的风险及对策,得出隧道进口段较适宜TBM施工,但大直径TBM施工风险较高,推荐采用小直径TBM快速施工平行导坑方案;针对断层破碎带、节理密集带等特殊地层,提出设置辅助坑道来提前施工,然后TBM步进通过的方案。并从施工难度及风险、施工通风、施工排水、辅助坑道条件、运营维护及防灾救援、施工工期、工程投资等方面综合分析论证,推荐采用"钻爆法单洞双线隧道+贯通平行导坑(进口敞开式小直径TBM)"方案。

Research on TBM Construction Scheme of Ganqing Tunnel on Xining-Chengdu Railway

Based on the various characteristics of Ganqing Tunnel, such as high altitude, complicated geological conditions, fragile ecological environment and poor setting conditions of tunnel service gallery, the shortcomings of drilling and blasting method are analyzed and the feasibility of Tunnel Boring Machine method is explored. According to the geological survey data of different sections, the risks and countermeasures of TBM method are analyzed. The analysis results show that the TBM method is suitable for tunnel entrance construction, however, the large-diameter TBM may cause construction risks, and constructing parallel heading with small-diameter TBM maybe a more appropriate approach. For special strata such as fault fracture zone and jointed dense zone, excavating through service gallery in advance is recommended. Then a comprehensive analysis is conducted based on multiple factors, such as construction difficulty and risk, construction ventilation, construction drainage, auxiliary tunnel conditions, operation and maintenance, disaster prevention and rescue, construction period and project investment. The results indicate that a two-track and one-road tunnel constructed by drilling and blasting method and a parallel heading constructed by small-diameter TBM would be appropriate.