大断面花岗岩公路隧道快速施工工法研究

Research on rapid construction method of large section granite highway tunnel

大断面隧道施工穿越较破碎花岗岩区段时,采用台阶法开挖会造成工序之间相互影响,严重制约了大型机械的作业空间,为此在台阶法基础上提出了便于大型机械施工的快速施工工法,从而提高了施工效率。文章基于某高速公路隧道,通过有限差分软件,对快速施工工法和施工设计的台阶法留核心土开挖进行两榀开挖下的数值模拟对比分析,并结合FISH语言编程和现场监测数据验证了快速施工工法的围岩损伤及可行性。结果表明:快速施工工法与台阶法留核心土开挖相比,会增大隧道拱肩、边墙以及掌子面处的围岩变形;现场施工时要加强对隧道边墙下方和拱脚处的监测;快速施工工法是一种可应用于现场的、安全高效的施工工法。

The step method is commonly used to excavate the large section tunnel through the poor granite section,but it often causes the mutual influence between the working procedures,which significantly limits the working space of large machinery.To address this issue,a rapid construction method based on the step method is proposed,which facilitates the use of large machinery construction and improves the construction efficiency.Based on a certain high-speed tunnel,this paper uses finite difference software to compare and analyze the numerical simulation of the rapid construction method and the core soil excavation method with the step method designed by construction under two phases of excavation,and verifies the surrounding rock damage and feasibility of the rapid construction method with the combination of FISH language programming and field monitoring data.The results indicate that the rapid construction method increases the deformation of surrounding rock at spandrel,side wall and face of tunnel compared with the step method.During the field construction,the monitoring under the side wall and at the arch foot should be strengthened.The rapid construction method is proven to be a safe and efficient construction method which can be applied in practice.