海域复杂地质双模式TBM设备选型与应用关键技术

为解决青岛地铁长距离穿越埋深30~60 m海底微风化凝灰岩和500 m宽的F5断层破碎带时面临的突涌水风险等技术难题，从工期、地质、地下水3方面综合比选，确定双模式TBM施工，穿越海底硬岩地层段采用TBM敞开模式掘进，穿越F5断层破碎带由敞开模式转换为土压平衡模式掘进。基于特殊工况下的水文地质环境，开展TBM设备选型与优化改造，增加盾尾刷以提高设备防渗能力，盾尾设止浆板保证壁后注浆效果；配备超前地质钻机和双液注浆设备，实现超前钻探和注浆加固；采用重型合金刀，减少换刀频率并增加开挖尺寸，降低复杂地质卡机风险；刀盘开口位置增设钢格栅，防止大块度洞渣破坏刀盘；压力隔板上增加超前孔，实现无压模式正面钻探及注浆加固。拆除主皮带机及相关设备，封堵压力隔板孔洞，安装螺旋输送机及泡沫系统，由敞开模式转换为土压平衡模式，提高双模式TBM穿越破碎带的安全性。通过设备选型与优化、工艺试验、模式转换研究，顺利完成了青岛地铁8号线大洋站—青岛北站区间穿越海域复杂水文地质辅助导洞施工。

Key Technologies for Type Selection and Application of Double mode TBM in Complex Geology of Sea Area

The water inrush risk encountered in Qingdao Metro tunnel crossing submarine slightly weathered tuff with 30~60 m burial depth and F5 fault and fracture zone with 500 m width should be solved. The double mode TBM is adopted, the open mode of TBM is adopted for submarine hard rock section, and the soil pressure balance mode of TBM is adopted for F5 fault and fracture zone based on comprehensive comparison and selection on construction period, geology and groundwater. According to the hydrogeological environment under special working conditions, selection and optimization of TBM are carried out as follows: (1) The shield tail brushes are added to improve the equipment′s anti seepage ability; the shield plate at the tail of the shield is installed to ensure the grouting effect. (2) The advanced geological drilling rig and double grout grouting equipment are equipped to achieve advanced drilling and grouting reinforcement. (3) The heavy alloy cutters are adopted to reduce the frequency of tool replacement and the size of excavation face is increased to reduce the risk of TBM jamming due to complex geology. (4) The steel grille at the opening position of the cutter is added to prevent large amount of hole slag from damaging the cutter. (5) The holes on the pressure separator are added to realize no pressure mode front drilling and grouting reinforcement. When crossing fault and fracture zone, the belt conveyor and related equipment are removed, the holes in the pressure separator is sealed, the screw conveyor and foam system is installed to change the open mode to the earth pressure balance mode, so as to improve the safety of the double mode TBM. Through the research of optimization of equipment, process test, mode conversion of TBM and soil pressure balance, the construction of auxiliary guide tunnel for Dayang Station North Qingdao Station of Line 8 crossing complex hydrogeology of sea area is successfully completed.