Research purposes: This paper relies on the project of the tunnel of Tianjin Metro Z2 underneath passing through the Binhai Airport,considering the airport non-stop flighting, analyzes the deformation of the runways of airport flight area caused by double-line shield tunnels undercrossing in the soft soil area, and explores the effects of shield burial depth and deep hole grouting circle thickness on the sedimentation of the runway, to obtain a suitable shield burial depth and deep hole grouting circle thickness,and analyzes its regularity on the sedimentation of the runway, providing guidance for the construction of double-line shield tunnels undercrossing non-stop airport runway in the soft soil area.
Research conclusions: (1) Increasing shield burial depth and deep hole grouting circle thickness can effectively reduce the settlement and the rate of difference settlement of the runway, but the reduction effect on the settlement does not become more effective with the increase of deep hole grouting circle thickness.(2) After the double-line tunnel excavation is completed, the horizontal settlement curve of the runways presents the "V" shape. Because of the stacking effect of double-line shield tunnels successive construction, the maximum settlement position is closer to the tunnel of the later excavation. (3) At the same buried depth, the influence of the tunnel of the later excavation on the settlement of the runway is less than the impact of the tunnel of the first excavation on it, and with the increase of the thickness of the grouting circle, the impact of the tunnel of the later excavation on the settlement of the runway is getting smaller and smaller.(4) During the double-line tunnel excavation, the rate of difference settlement of the runway increases, and then decreases, and finally stabilizes. (5)The research result provides a reference and construction guidance for the shield burial depth and deep-hole grouting design in the project of double-line shield tunnel undercrossing airport runways in the soft soil area.