Analysis of ground settlement induced by Earth pressure balance shield tunneling in sandy soils with different water contents

Abstract

In this paper, reduced-scale tests and numerical simulations were used to investigate the response of sandy soils with different water contents when Earth pressure balance shield (EPBS) tunneling was conducted. Both surface and subsurface settlement of the ground were analyzed, and the settlement data were fitted with different equations from previous studies. The results showed that the water content in a sandy soil has a significant effect on both the profile and magnitude of the settlement of the surface and subsurface. When the water content was less than a certain value, the increment of water content obviously contributed to decrements in the magnitude of ground settlement, and there was an obvious increment in the coefficient of the width of the settlement trough width and a simultaneous greater degree of nonlinearity for the ground settlement parameter (K) in the subsurface. When the water content was greater than this certain value, the increment of water content produced the opposite results. Both the modified Gaussian curve and the yield density curve provide better fits of the data for the settlement of the surface of dry, sandy soil than the Peck curve. When the water content was less than this certain value, the three curves for the subsurface settlement data were almost the same. When the water content was greater than this certain value, the modified Gaussian curve and the yield density curve provided better fits of the surface settlement data than the Peck curve.