Numerical Simulation Analysis of Influence of Position and Thickness of Weak Interlayer on Tunnel Excavation
In response to the impact of weak interlayers on tunnel excavation,the position(1.5 d,2 d,2.5 d)and thickness(1 m,1.5 m,2 m)of the weak interlayers are taken as the research object.By using numerical simulation analysis software Midas GTS NX,a numerical model for full section step-by-step excavation under 9 working conditions is established,and calculation and analysis are carried out by monitoring sections A(y=5 m),B(y=10 m),and C(y=15 m).The results show that among the deforma-tion values of key points on monitoring surfaces A,B,and C,the deformation of the arch top and arch bottom is the largest,fol-lowed by the deformation of the arch wall and arch foot.The closer the position of the weak interlayer is to the tunnel,the greater the deformation of each key point.Secondly,the thicker the weak interlayer,the greater the deformation of each key point.In tunnel ex-cavation projects with weak interlayers,measures should be taken to control the impact of weak interlayers on tunnel excavation.