Model tests on tail-grouting process during URUP shield tunneling in soft soil. (September 2020)

• Record Type: Journal Article
• Authors: Liu, Chao; Li, Jiasen; Zhang, Zixin; Li, Pan; Cui, Jie; Liu, Hai; Yang, Yubing
• Is Part Of: Tunnelling and underground space technology. Volume 103(2020)
• Publication Date: 2020-09
• Subjects: URUP -- Model test -- Tail-grouting -- TBM; Tunneling -- Periodicals; Underground construction -- Periodicals; Tunnels -- Periodicals; Underground areas -- Periodicals; 624.193
• DOI: 10.1016/j.tust.2020.103451
• Languages: English
• ISSNs: 0886-7798

Abstract

Abstract: This paper investigates the process of tail-grouting during tunnel excavation using the URUP (Ultra-rapid Underpass) method. A small-scale model test was conducted to investigate the grouting-induced influence on surrounding soils and the filling process of the grout mortar during URUP tunneling. Particular attention was paid to tunneling phases with negative and shallow overburdens. In addition, ground responses including surface settlement, grouting pressure and earth pressure around the tunnel were monitored in the experiment. Combined with the experimental observation, the grouting effect behind the tunnel linings under different overburdens was analyzed. According to the experiment results, the grouting pressure was not uniformly distributed within the tail-void, with the maximum magnitude monitored adjacent to the injection openings. The earth pressure was more sensitive to the grouting volume ratio than to the pause/restart of tail-grouting operation, and the surface settlement was positively correlated to the grouting-volume ratio (GVR) during tail-grouting. The influence zone of each opening was not uniform and symmetric within the tail-void. The experiment suggested a reasonable GVR range of 130–160% for the URUP tunneling with a shallow overburden. For negative overburden phases, a GVR smaller than 145% is suggested to avoid unexpected overflow to the ground surface during tail-grouting.