水下盾构隧道硬岩处理与对接技术

为了对盾构隧道(尤其是水下盾构隧道)施工中遇到的特殊地层的处理方法进行总结,特别是阐明水下盾构对接施工的关键技术,以借类似工程参考。结合目前盾构隧道施工实践,分析在软硬不均地层、孤石地层、卵砾石地层中利用盾构法修建隧道的主要问题和困难,相应地提出了一些基本措施和技术对策。结合台山核电站取水隧洞(位于海域中)盾构施工中遇到的微风化花岗岩硬岩(最高强度达197 MPa)和球状风化孤石,提出了水下爆破法和冲击钻冲孔2种方法进行基岩突起和孤石处理,盾构顺利通过该基岩段,没有进行刀具更换。结合3次穿江越洋的狮子洋盾构隧道的水下对接(国内首次)问题,分析总结了"相向掘进、地中对接、洞内解体"的关键技术,对接非常成功,对接点的围岩相对稳定,精度符合要求。

Case Study on Hard Rock Treatment Technology and Shield Docking Technology in Boring of Underwater Tunnels

The treatment of special ground encountered during underwater shield tunneling is summarized. The shield docking technology adopted in boring of underwater tunnels is presented. Main difficulties of shield tunneling in hetero- geneous ground, boulder ground and gravel ground, as well as the corresponding countermeasures, are analyzed. In the shield tunneling through slightly-weathered hard granite ground and weathered boulder ground in the construction of the water conveyance tunnel of Taishan Nuclear Power Station, underwater blasting technology and impact drilling technology for bedrocks and boulders are applied. The shields have successfully passed through the bedrock section, without cutting tool replacement. In the construction of Shiziyang underwater tunnel, shield docking technology is adopted. The docking has achieved good result, the rock mass at the docking point is stable and the docking accuracy is high.