软弱破碎围岩高铁隧道压力拱演化规律分析

Analysis on pressure arch evolution law of high-speed railway tunnel under unfavourable rock conditions

选取双线高铁隧道为研究对象,对隧道开挖过程中压力拱的形成及发展规律进行研究,得到以下结论:1)压力拱的演化规律分为三个阶段,即外边界形成阶段,内边界连通阶段,内、外边界发展阶段.2)对于软弱破碎围岩而言,应在压力拱发展的第一阶段,采取适当的超前支护措施,防止隧道周围松动区的连通.3)为了保证隧道施工过程中的安全,建议超前预支护的长度应大于1倍隧道跨度,重点对隧道的拱部180°范围进行预支护.相关研究成果为确定超前预支护时机及范围提供参考,对支护设计和指导隧道施工有着重要的意义.

According to the double-track high-speed railway tunnel,the formation and development of pressure arch are studied. The conclusions of the research are as follows. 1） The pressure arch evolution law is divided into three stages,namely the outer-boundary-forming phase,the inner-boundary-connecting phase and the inner-and-outer-boundaries-developing phase. 2） For unfavourable rock,appropriate advanced support measures should be taken in the first phase to prevent the connection of the disturbed zone around the tunnel area. 3） To ensure the safety of the construction process,the length of advanced support should be longer than the tunnel span and its support range should be more than 180°. The results can provide references to determine the timing and support range of the advanced supports,and have an important guiding significance to the support design and construction of the tunnel.