Connecting arch tunnels;  ground inclination;  bias;  construction optimization;  Construction mechanics

Based on the plane strain problem, the Druck-Prager yield criterion was used to study the influence of different surface inclination angles on the construction mechanical properties of different construction methods of biased continuous arch tunnels. Through the analysis of the mechanical characteristics of the secondary lining of the tunnel and the force of the middle partition wall, the optimal construction method was determined. The simulation results show that when the ground inclination angle is 5°~15°, it is advisable to excavate the side with a small burial depth first. When the inclination angle of the ground is 15°~30°, if the stability of the middle partition wall can be ensured, it is advisable to excavate the side with a smaller burial depth first; On the contrary, it is advisable to excavate the side with a larger burial depth first; The safety factor of the wall foot of the first excavation cave chamber is small, and attention should be paid to strengthening it during construction.