长沙营盘路湘江隧道分岔大跨施工技术

长沙营盘路湘江隧道匝道与正洞分岔合流大跨段断面大、变化多、埋深浅、地质差、受力变形复杂。为了安全顺利地完成合流大跨段开挖，介绍了一套完整的分岔大跨合流段施工技术，并对开挖断面渐变分部、异型二次衬砌等关键控制技术进行了详细阐述。实践证明，本分岔合流段大跨在埋深浅、地质差、环境复杂的情况下采用合适的地层加固措施、不同断面的合理渐变、超大断面的合理分块、保留临时支撑施作二次衬砌等技术是切实有效的，可为其他类似工程施工提供参考。

Construction Technology for Fork Section of Yingpanlu Xiangjiang River Crossing Tunnel in Changsha, China

The junction section of Yingpanlu Xiangjiang river crossing tunnel has changing large cross section, shallow overburden, poor geological conditions and complex stressing conditions. The technologies used for the construction of the fork section of the tunnel, especially the excavation sequence and the secondary lining of the tunnel section with changing large cross section, are presented in the paper. The practice demonstrates that the technologies adopted are feasible for the specific conditions of the works. 