穿越湘江水下岩溶发育区地铁盾构选型研究与应用

长沙地铁3号线越江隧道穿越湘江岩溶发育区,盾构施工风险高。针对沿线砾岩夹泥质砂岩复合地层、断裂破碎带和复杂岩溶地层等特殊地质条件,考虑水下高水压等因素影响,对地铁盾构选型进行研究。考虑不同施工风险,对盾构各关键部分进行设计与改进;对岩溶地层进行注浆预加固处理,分析泥水盾构对穿越复杂岩溶地层的适应性。采用改进的泥水盾构成功穿越湘江水下岩溶发育区,掘进效果良好,表明泥水盾构选型对穿越湘江水下岩溶发育区隧道的施工环境是合理且适应的。

Research and Application of Shield Selection of Metro Passing through Karst Development Area under Xiangjiang River

The cross-river tunnel of the Changsha Metro Line 3 passes through the karst development area under the Xiangjiang River and the risk of shield construction is high. We performed research regarding the metro shield selection in terms of the special geological conditions along the line such as conglomerate and argillaceous siltstone mixed strata, fault fracture zone and complex karst strata. In addition, we also considered the influence of high-water pressure and other factors. Designs and improvements were implemented for the key parts of the shield considering the different construction risks; the karst strata were pre-reinforced by grouting and the adaptability of the slurry shield to cross complex karst strata was analyzed. The slurry shield successfully crossed karst development area under the Xiangjiang River and the effect was good while digging. This indicates that the selected slurry shield is reasonable and adaptable to the construction environment of the tunnel crossing karst development area under the Xiangjiang River.