Ground deformation induced by shield tunneling posture in soft soil

Abstract

Constructing tunnels in soft soil using shield machines would induce soil deformation. Several factors, such as support pressure, ground loss, grouting pressure may affect the soil deformation. In engineering practice, the ground deformation could also vary with the posture of the shield machine. This study proposed an approach for estimating the soil deformation considering shield posture. Firstly, the shield-soil interaction displacement was obtained by considering shield geometry and its kinematic behavior, such as shield diameter and length, articulation, and shield deviation. Secondly, based on the elastic half-space theory, a calculation method for mapping the shield-soil interaction displacement to soil deformation was established. Finally, the proposed model was verified by the field measurement in the tunnel of Suzhou Metro line S1, and the results confirm that the postures of the shield machine in the soil influence the magnitude, distribution, and evolution of the soil deformation.