【摘要】 分岔隧道是一种新型的隧道结构形式,其设计方案、开挖支护方法对围岩稳定性至关重要。以沪蓉西高速公路庙垭隧道为工程背景,基于大拱段跨度大、浅埋等工程特点,通过围岩变形监测、支护体系受力监测和爆破振动现场监测,分析分岔隧道大拱段围岩变形特点和控制措施,并探讨爆破振动对浅埋地表稳定性的影响,得到浅埋大拱隧道施工开挖的围岩变形规律、支护体系受力状态以及其爆破振动效应的特点,判定浅埋山体的稳定性及支护参数选取的合理性。该研究为分岔隧道的现场施工提供了必要的依据,对今后类似工程的设计和施工具有重要的参考价值。更多还原

【Abstract】 Bifurcated tunnel is one of the new type tunnelst,he excavation way and support style are key factors to the rock stability.A case study of Miaoya bifurcated tunnel is given;based on the character of large-span shallow part of bifurcated structure,the contents,technique,and method of monitoring in large-span shallow section are presented.Based on the measured data,such as the ground settlementr,ock deformation,bolt axial force,concrete ling stress and so on,the deformation and stress properties of surrounding rocks and supporting system are analyzed;in addition to the blasting dynamic characteristics of ground vibration for the serious blasting damage of shallow ground vibration,the in-time information is applied to guide tunnel construction and optimize the supporting system,and monitoring results are discussed in detail.The study provides indispensable evidence for the design and construction of the bifurcated tunnel.更多还原