A large-scale synchronous grouting test for a quasi-rectangular shield tunnel: Observation, analysis and interpretation

• Published in: Tunnelling and underground space technology 2019-09, Vol.91, p.103018, Article 103018
• Main Authors: Zhao, Tianchi, Ding, Wenqi, Qiao, Yafei, Duan, Chao
• Format: Article
• Language: English
• Subjects: Mock-up test; Quasi-rectangular shield; Simulation framework; Soil deformation; Synchronous grouting
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2019.103018

•A large-scale mock-up test is carried out to study the behavior of synchronous grouting in a quasi-rectangular shield tunnel and its influence on the movement of around soil.•Two time-dependent formulations are developed to describe the evolution of grouting pressure and hardening of grout in the synchronous grouting, respectively.•An advanced simulation framework is proposed and validated via the analysis of results from the large-scale mock-up test, and used to interpret the test observations.•Sensitivity analyses of the grouting pressure, the material types of grout and the shape of tunnels are implemented to study the influence of key factors on the grouting result. Synchronous grouting is one of the most vital processes during the construction of shield tunnels, especially the one with a special non-circular profile. This paper presents a large-scale mock-up test aimed to study the behavior of the synchronous grouting in a quasi-rectangular shield tunnel and its influence on the ground movement. Both the test results and the literature data reveal that the grouting pressure changes with time according to a power function while the hardening of grout could be described by a logarithm function. Incorporating these two new formulations, a novel simulation framework is proposed to interpret the observation during the mock-up test. Moreover, the effects on the ground movement of the grouting pressure and the grout types are highlighted and discussed via sensitivity analysis. The results demonstrate that the grouting pressure dominates the upheaval of ground while its dissipation and the solidification of grout control the following settlement. The effect of the quasi-rectangular shape on the ground movement is also investigated.