营盘路湘江隧道江底大跨段施工风险控制与安全性分析

为确保复杂条件浅埋大跨水下隧道施工安全,正确评估江底大跨段地层加固措施、施工工法及支护参数的可靠性,以长沙市营盘路湘江隧道西岸北线大跨段工况为实例,通过工程类比提出设计施工方案,实施前进行三维数值分析评估及现场验证。得出以下结论：提出的辅助措施、支护参数和施工工法能保证隧道的开挖安全;影响隧道施工安全的关键部位是左右导洞小间距段的中间岩柱以及与大跨段的连接局部范围,应着重加强支护。

Construction Risk Control of and Safety Analysis on Underwater Large-span Sections of Xiangjiang River Crossing Tunnel on Yingpan Road

The large-span section on the west shore of the north tube of Xiangjiang River Crossing Tunnel on Yingpan Road in Changsha City is a shallow-buried,large-span underwater tunnel section under complex conditions.The construction design is determined by means of engineering analogy.3D numerical assessment and test in the field are carried out before construction so as to assess the safety of the ground reinforcing technology,the construction methods and the lining parameters of the underwater lager-span section.Conclusions drawn are as follows： the excavation safety can be guaranteed for the sake of the assistant measures,the lining parameters and the construction methods adopted;the pillar of the small-spaced section between the left drift and the right drift and the connection positions of the large-span section are critical parts that have impact on the tunneling safety and should be strengthened.