Research on Transversal Settlement Characteristics of Strata Caused by Large Diameter in Shield Tunneling Slurry Pressure Balance

Based on on-site measured long-term soil settlement data, the Peck empirical formula was used to study the shape, width coefficient and influence range of transversal settlement troughs of ground and deep strata. The results showed that: 1) The long-term settlement of strata caused by shield tunneling, whether it was transversal settlement of ground or deep stratum settlement, conformed to the Gaussian distribution. Affected by the consolidation of disturbed soil, the settlement trough gradually deepened and widened. 2) From the perspective of ground settlement, the transversal settlement caused by shield tunneling construction was in a range of 1.4 times tunnel diameters, which would increase to a range of 2.3 times tunnel diameters due to long-term consolidation of soil. For the deep stratum settlement (buried at a depth of 12.1 m), the affected range by shield tunneling was 0.8 times of tunnel diameters, and over time, the affected range would expand to a range of 1.2 times tunnel diameters. The affected range by shield tunneling in the deep stratum was smaller than that in the ground. 3) The settlement width coefficients of the ground and deep stratum conformed to an exponential distribution with the time of disengagement of the shield tail from the measured cross-section, and leveled off eventually. However, the growth rate and amount of the width coefficient of ground settlement troughs were greater than those of deep soil. 4) The transveral settlement curve the of deep stratum was steep, while the transversal settlement curve of the ground was relatively flat. The curvature of the transversal settlement curve of the deep stratum was larger and more concentrated than that of the ground.