Finite Element Analysis of Pipe Shed Pre-Supporting Reinforcement Effect on A Shallow-Buried Tunnel

Abstract

Abstract Under the engineering background of crushed zone at the entrance section of a shallow-buried soft rock tunnel, the 3D finite element simulation of pipe shed pre-reinforcement measures was implemented under different diameters, lengths, and spacing via Midas Civil software after the excavation of tunnel portal, in an effort to analyze the reinforcement principle of pipe shed grouting reinforcement method during the tunnel excavation process. The stress-induced deformation laws of the support system were summarized, and the reinforcement effect of pipe shed grouting method was analyzed. The results show that with the increase in diameter of pipe shed, the maximum deformation of pipe shed is obviously reduced, and the favorable effect is reached when the diameter of pipe shed is within 300-600 mm. As the pipe shed extends to the undisturbed zone of soil mass, the change in length has a very minor effect on the deformation of pipe shed, while the deformation is greatly impacted by the excavation footage, and the deformation becomes the most significant after the excavation footage becomes greater than 1.5 m.