高地应力条件下深埋隧道开挖方式数值优选及工程应用

Numerical Optimization on the Selection of Excavation Methods for Deep Tunnels in High Stress Field and its Engineering Application

针对高地应力条件下隧道全断面施工过程中出现的挤压掉块、支护结构扭曲破坏等现象,拟采取上下台阶法或下导洞超前开挖法进行施工,现利用有限差分软件FLAC3D模拟分析了全断面法、下导洞超前开挖法、上下台阶法3种开挖方案,对比分析位移场、塑性区和应力场的分布特征,结果表明:综合考虑位移场、塑性区及应力场分布等关键特征,推荐采用上下台阶法进行现场施工,采用该方法施工后开挖面稳定性得到明显改善,且现场监测数据与数值计算结果较为吻合。

To avoid rock falls and distortion of support structure occurring in the construction of tunnels in high stress field, the designers had plans to use either stage excavation or pilot heading excavation method for the tunnel. Full face excavation method, pilot heading excavation method and stage excavation method were simulated by the finite difference sotiware FLAC3D. After analyzing and comparing the features of the distribution of the deformation field, plasticized deformation field and stress field, the stage excavation method was proposed for the tunnel based on the data produced. After adopting the said method, the stability of the excavation face was improved dramatically and the data collected at the site coincide well with the numerical simulation results.