Abstract:

The pressure gradient in slurry chamber is difficult to keep consistent with that of the soil and pore water in the stratum during slurry shield tunneling, and especially for large crosssection shield; the top slurry pressure is observably greater than soil and pore water pressure, which makes the excavation confront severe risks of passive failure. Therefore, it is necessary to summarize and analyze the research progress of the passive failure of excavation face, and point out the problems in the study of the passive failure of excavation face of slurry shield in sandy stratum. The research progress is summarized from the aspects of limit analysis method research, numerical simulation and model test; and then the problems existing in the study are analyzed as follows: (1) The research on slurry breaking through filter cake which leads to splitting failure and affects excavation face stability is in absence. (2) With the limit of experiment conditions, study of largediameter excavation face passive failure has not been carried out, particularly the centrifugal model test for excavation face during dangerous geological conditions , i.e. accessing to an excavation chamber under airsupport system. (3) The excavation face of shield is simulated by rigid plate in centrifugal model test, which is distinct from the actual force and deformation of the soil. Finally, the main research directions are put forward for future research.

Key words: slurry shield, excavation face, sandy stratum, passive failure, model test