隧道洞口偏压段斜交套拱施工技术及弹塑性数值模拟分析

Construction Technology and Elastic-Plastic Numerical Simulation Analysis of Skew Arch Sleeve in Biased Section of Tunnel Portal

在山区高速公路、铁路建设中,由于受其地形、地貌制约,偏压隧道设计愈来愈常见,隧道与山体斜交的情况也愈加普遍。对此,以石忠高速公路某隧道工程为研究对象,基于其隧道斜交洞口的地形、地貌和地质实况,对不同进洞施工工艺进行对比分析,最终选用斜交套拱配合长大管棚提前支护进洞工艺进行施工;阐述该工艺流程及关键控制点,并对偏压段斜交套拱施工技术进行弹塑性数值模拟分析,结果表明该技术不仅能减少洞口段的大面积开挖、有效保护自然环境及山体稳定,同时也确保了施工安全。

Due to the objective constraints of landform and design needs of mountainous expressway,not only biased tunnel is becoming increasingly common,but also the oblique intersection between tunnel and mountain is becoming more common.Taking a tunnel of Shizhong Expressway as the research object,according to the actual terrain,landform and geological conditions of the tunnel skew portal,through careful comparative analysis of different tunnel entry construction processes,the construction process and key control points are introduced by selecting the skew arch sleeve combined with the long pipe shed to support the tunnel entry in advance.The elastic-plastic numerical simulation analysis is carried out.The simulation results show that the construction technology of skew arch sleeve at the biased section of the tunnel portal not only reduces the large-area excavation of the portal section,effectively protects the natural environment and mountain stability,but also ensures the construction safety.