Ground settlement caused by large-diameter slurry shield during tunnel construction in soft soils

To study the ground settlement caused by large-diameter slurry shield during tunnel construction in soft soils, the formulas are proposed on the basis of the Mindlin solutions. The effects of unit weight of slurry on the additional pressure around cutting head, the effects of shield gravity on the non-uniform distribution of softening skin frictions along the shield, the dissipation of grouting pressure along the lining rings and the ground deformation caused by volume loss ratio are considered in the proposed solutions. The calculated and field results are compared through a typical engineering case. The results show that: (1) Without considering the unit weight of slurry, non-uniform distribution and circumferential dissipation, the heave of ground longitudinal displacement is overestimated, and the settlement value is underestimated. The calculated results of longitudinal deformation by the proposed method are in good agreement with the measured results. (2) The calculated results of transverse deformation by the proposed method are in good agreement with the measured results. The transverse deformation of ground surface induced by large-diameter slurry shield is close to normal distribution. The results can provide scientific reference for the prediction and control of ground deformation induced by large-diameter slurry shield.