隧道洞口偏压段洞门开挖,应遵循早进洞,减少植被破坏,保证边坡稳定,快速、有效的形成洞门的原则。为保障隧道安全、顺利进洞,永宁高速公路高增隧道左洞出口进洞施工,采用了斜交套拱联合大管棚预支护施工技术,该技术对类似工程具有借鉴参考作用。 The excavation of the tunnel gate at the biased section of the tunnel entrance shall follow the principle that the hole is advanced as early as possible to reduce vegetation damage and ensure the stable, rapid and effective formation of the tunnel door. In order to ensure the safety of the tunnel and smoothly enter the hole, the left-hand exit of Gaoseng Tunnel of Yongning Expressway is used for the construction of the tunnel. The construction technique of pre-supporting with large-shed and skewed arch is adopted. This technology has reference and reference function for similar projects.