Analysis of Surrounding Rock Disturbance in Shallow Buried Double-Side Biased Small Clear Distance Tunnel

Abstract

In order to explore the surrounding rock disturbance in the shallow buried double-sided biased small clear distance tunneling process, relying on a national highway project, the finite element Midas Gts Nx was used to conduct numerical simulation analysis of the tunnel construction process, in order to analyse the law of surrounding rock stress and strain in the shallow buried double-sided biased small clear distance tunneling process. The results show that the subsidence shape of surface slope develops from “V” shape to “W” shape, and the vertical horizontal displacement shape of septal rock changes from “V” shape to “W” shape. The surrounding rock produced a certain amount of uplift halfway up the mountain. When the rear tunnel is driven, the centre of gravity of the septum rocks migrates towards the rear tunnel side, which reduces the stress of the surrounding rock at the front tunnel and is conducive to the stability of the front tunnel structure. The stress increase of the middle barrier rock at the arch foot is obvious and it has the characteristic of through-through. The stress of the structure at the tunnel wall foot should be monitored emphatically during construction. When the rear tunnel is driven, the plastic zone of surrounding rock appears on the diagonal of the septum rock, and the safety factor of surrounding rock is increased and the speed is reduced. Numerical simulation can provide theoretical guidance for field monitoring and measurement.