A Large-Scale Synchronous Grouting Test for a Quasi-Rectangular Shield Tunnel: Observation, Analysis and Interpretation

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.