华蓥山隧道浅埋段明挖改暗挖施工技术研究

Research on the Construction Technology of Changing Open Excavation to Underground Excavation in the Shallow-buried Section of Huayingshan Tunnel

文章以西渝高速铁路华蓥山隧道4号明洞为例,为减少原生态坡面植被破坏,采用拱盖法暗挖施工。通过实地监测与有限元极限分析法,分析了初支拱盖法的施工力学特性。结果显示,拱盖护拱能限制围岩变形,确保施工稳定;预加固桩可稳定边仰坡和侧翼围岩;拱脚处和隧道下部是变形关键部位。有限元分析结果与现场吻合,按该设计施工,隧道已顺利通过明挖段。

Taking the No.4 open cut tunnel of Huayingshan Tunnel on Xi'an-Chongqing High-speed Railway as an example,in order to reduce the damage to the original ecological slope vegetation,the arch cover method is adopted.Through field monitoring and finite element limit analysis,the construction mechanical properties of the initial support arch cover method are analyzed.The results show that the arch cover protective arch can limit the deformation of surrounding rocks and ensure the stability of construction;the pre-reinforced piles can stabilize the surrounding rocks at the side slope and the flank;the arch foot and the lower part of the tunnel are the key areas for deformation.The finite element analysis results are consistent with the site.According to the design for construction,the tunnel has successfully passed the open excavation section.