Mechanical Study on Leading Ductule and Pipe Roof Pre-Support Technologies in Tunnel Excavation

For the purpose of ensuring the construction safety of tunnel excavation, it is necessary to adopt a suitable pre-support technology to reinforce the surrounding rock. The pipe roof reinforcement method and the leading ductule method are the most commonly used and classical technologies during tunnel construction. This paper adopts the Huashan tunnel and the Xianglianshan tunnel as the engineering background, the numerical simulation is established based on Midas/GTS to analyze the mechanical performance of the pre-supports formed by the two methods during excavation, then the obtained results, such as stress, deformation, plastic zone, and settlement, are analyzed and discussed. The analysis and discussion illustrate that, during excavation, compared to the leading ductule reinforcement method, the pipe roof reinforcement method can effectively control the vault settlement and improve the stress state of the lining structure, as well as prevent the stress release from the surrounding rock. Thus, the pipe roof reinforcement method shows better reinforcement effectiveness and ensures construction safety.