Abstract: Slurry shield tunnelling method is widely used in the complex geological environment with high water pressure for tunnel construction. The face stability control is the key for the engineering safety during shield tunnelling. Due to the continuous rotation of the cutter head, the filter cake is in the "formation-destruction-re-formation" dynamic cycle process, resulting in a relative permeable membrane. How to evaluate face stability under this dynamic filter cake need to be further explored. In this paper, the dynamic filter cakes are divided into three types. An analytical approach is developed by coupling the penetration-filtering and shield movement. Based on the pressure transfer mechanism of the bentonite suspension, a new penetration-type model for the evaluation of face stability is developed. It can be found that the slurry viscosity as well as the filter cake ratio should be paid more attention during tunnelling in the high permeable ground. A faster advance rate and a lower rotation speed of the shield machine could improve the face stability. Finally, a design chart of slurry support efficiency is provided, which could give some reference for the control of support pressure and slurry selection in engineering practice.

Key words: slurry shield tunnelling, dynamic filter cake, face stability, support efficiency, slurry selection