单跨4车道公路隧道拱顶外露盖挖施工技术

Study on Technology for Covered Excavation of Vault Exposure in Huge Section Tunnel

京沪高速济南连接线工程浆水泉隧道穿越黄金谷风景区,该区段属浅埋、超浅埋、局部浅埋及外露等突变地形,施工难度大,环保要求高。为顺利通过本段施工,对该区段的地质情况和周边环境及要求进行全面分析和总结,确定了对拱顶外露区段采用盖挖法施工,即先小范围挖方,施工拱盖后,在拱盖保护下再进行洞内暗挖的施工技术,减少了对山体的扰动,降低了对风景区的环境破坏,提高了施工速度,并通过数值模拟分析,对盖挖法施工后隧道围岩的应力应变情况进行分析。结果表明采用该施工方法的隧道安全性满足要求,供类似工程参考。

Jiangshuiquan tunnel,which is located at Jinan connecting line of Beijing-Shanghai Expressway,passes through Huangjingu scenic spot.This section belongs to shallow buried,super-shallow buried and exposed topography.It is difficult to construct and requires high environmental protection.For the smooth passing section of construction,the covered excavation method is adopted for the construction of the vault exposure based on the comprehensive analysis and summary of the geological conditions and surrounding environmental requirements,that is,firstly small-scale excavation,then the construction of the arch cover,finally under the protection of the arch cover for the tunnel construction.This technology reduces the disturbance to the mountain,reduces the environmental damage to the scenic area,and speeds up construction.By numerical simulation analysis,the stress and strain of surrounding rock after construction with covered excavation method are analyzed.The results show that the method meets the safety requirements and the conclusions can be used for reference in similar projects.