On Segment Floating and Relevant Mechanical Behaviors during Large-Diameter Shield Tunnelling
(1 School of Civil Engineering, Central South University, Changsha 410075; 2 The Third Railway Survey and Design Institute Group Corporation, Tianjin 300142)
Abstract：
In light of the causes of segment uplift during large-diameter shield tunnelling, this paper introduces the typical segment uplift of the river-crossing highway tunnel of Nanhu Road in Changsha City. The final segment floating value was calculated based on the relevant mechanical analysis and elastic mechanics theory and considers the compression effect on the overlaying grout/soil mass induced by the segment floating. The influences of calculation parameters such as geological conditions, grout quality, bolt shear force and residual force of the jack on the final uplift were obtained through a sensitivity analysis. The rationality of the proposed uplift formula was verified based on the project case and the buoyance applied on the segment section was given by an inverse method; corresponding anti-uplift measures were proposed based on the research results and engineering practice.
2016, Vol. 53 