Numerical simulation analysis of tunnel construction mechanical response considering shotcrete hardening process

Abstract

Abstract At present, tunnel construction mechanics studies basically do not consider the hardening process of shotcrete. In order to reveal the hardening process of sprayed concrete in a sulfate environment and the influence of sulfate corrosion on tunnel stability, the model parameters were determined in combination with the change rules of mechanical parameters of shotcrete obtained in the author’s experiment. The MIDAS GTSNX finite element software was used to analyze the effect of the hardening process of the shotcrete, chemical corrosion, and physical corrosion of sulfate on the displacement and stress of the surrounding rock of the tunnel. The results show that considering the hardening process of shotcrete, the growth rate of tunnel clearance displacement increases, and the stress increase slows in the early stage of shotcrete (The tunnel lining structure is applied, and the second step of excavation is carried out). With the increase of time or the construction steps, the stress of shotcrete increases significantly, and the clearance displacement growth rate significantly decreased. The influence of the chemical and physical corrosion of shotcrete on the stress and displacement of the surrounding rock of the tunnel is similar to considering the hardening process of shotcrete. indicating that sulfate corrosion has an inhibitory effect on the hardening process of shotcrete and increased construction risk.