复杂地质海底隧道设计

Design of the Complex Geological Subsea Tunnel

研究目的:台山核电海底隧道工程是我国首条盾构海底隧道,隧道外径9 m,穿越中风化岩层、软土、砂层及土石交界面,地质条件复杂且位于海底。主要工程特点:大直径、长距离、复杂地质条件下盾构施工。存在难点包括:隧道工法选择、纵断面设计、结构设计、盾构选型及刀盘设计、盾构穿越土石分界及孤石群处理方案。通过理论分析研究和工程类比,确定安全合理设计方案。研究结论:(1)本工程海底隧道设计采用复合式泥水平衡盾构,钻爆法结合盾构法施工,通用管片+二次衬砌的复合式衬砌模式,能有效解决复合地层长距离水下掘进难题;(2)复合式盾构刀盘设计、水下孤石爆破处理能有效地解决盾构在土石交界面掘进高风险、低效率的难题;(3)通过实践证明本工程设计能有效地解决海底隧道相关技术难点,施工风险得到有效控制,可为今后同类工程及海峡隧道研究建设提供借鉴。

Research purposes： The subsea tunnel project in Taishan nuclear power station is the first subsea shield tunnel in China with external diameter 9 m through middle weathered rock, clay, sand and the interface of soil and rock. The geological and geotechnical condition in this tunnel is very complex. The main character of this project is large diameter shield tunnel, long distance construction in complex geological strata. The difficulties include tunneling construction method, longitudinal profile design, structure design, TBM selection and cutting head design, the treatment of tunneling through interface of soil and rock and boulders group. Through theory analysis and experience analogy, the safe and reasonable design scheme was demonstrated. Research conclusions： （1）The tunnel machine in this project adopt the mix- shield TBM, Shield tunneling method combines with New Austria Tunneling Method. The lining of the tunnel is combined type of universal segments lining and cast in concrete lining. It effectively solves the problem of long distance and under the sea tunneling. （2） The mix - shield cutter head design, boulders blast under the sea solves the problem of high risk and low efficiency speed of tunneling. （3） Through practice, it is demonstrated that this design can effectively solve the technical problems of subsea tunnel, and effectively control the construction risks, which can provide some references for the related projects and future channel tunnels construction.