Analysis of influencing factors in ground subsidence triggered by double-line tunnel excavation under different compressive states

The disturbance of shallow-buried tunnel excavation with large section is the main factor causing the ground subsidence, and the coupling effect between double-line tunnels makes the ground subsidence regularity more complicated. Based on the actual project, the law of ground subsidence and its influencing factors during the excavation of double-line tunnel under different compressive states are discussed by numerical simulation method. The results show that the ground subsidence curve of the double-line tunnel is asymmetrically W-shaped, and the maximum ground subsidence is inclined to the side with larger buried-depth; Under the non-biased state, the axial distance of the double-line tunnel has the most significant effect on the ground subsidence, while under the biased state, the influence factor is the transverse bias angle, and the maximum ground subsidence increases with the increase of the transverse bias angle. Based on the numerical results, three indexes are proposed to quantitatively describe the relationship respectively between the ground subsidence and the excavation section area, the axial distance of the double-line tunnel and the bias angle during the excavation of the double-line tunnel, and the indexes can be used to predict the ground subsidence triggered by the excavation of shallow-buried tunnel under the biased state. Furthermore, the study results can provide reference values for tunnel construction under similar conditions.