To ensure the mud discharge performance of the atmospheric cutterhead and reduce the risk of clogging, it is necessary to consider the distribution of soil in the cutterhead opening under different tunneling parameters. Taking the Haizhuwan tunnel project as an example, the rheological properties of soil and slurry samples were collected and analyzed. The full-scale mud discharge model of cutterhead was established for the first time by using the Euler multiphase flow model. By examining the pressure value of the monitoring point of the excavation chamber, the simulation parameters agree with the field-measured data. The simulation results show that the soil content in the center area and the edge area of the cutterhead is more than 60% and 15% respectively, which is much higher than that in other areas. The mathematical model of soil content and tunneling parameters was established, and the measures to reduce the soil content were explored. By comprehensively analyzing the variation law of soil content in the central and edge areas, it is beneficial to improve the mud discharge performance of the cutterhead by reducing the penetration rate and increasing the cutterhead rotation speed and grouting rate.

In the construction of slurry shield tunneling, the infiltration of slurry will cause excess pore water pressure in the surrounding soil. The distribution of excess pore water pressure and slurry infiltration zone are closely related to the stability of the tunnel face. Considering the influence of cutter head rotation and slurry specific gravity on pressure boundary conditions, this study proposed a multi-field coupling model to describe the dynamic transmission of excess pore water pressure and distribution of slurry infiltration range in three-dimensional. The temporal and spatial variation of soil pores characteristics parameters and slurry rheological properties owing to the deposition and diffusion of slurry particles is considered. The proposed model is verified by the in-situ testing measurements from in Beijing East Sixth Ring Road reconstruction project. In the prediction results, the spatial distribution of excess pore water pressure around the tunnel face appears bubble-shaped, and the shape of the slurry infiltration zone is close to flattened cake. The range of pressure dissipation and the thickness of particles infiltration zone are positively correlated with soil permeability coefficient, slurry pressure, while negatively correlated with the mass concentration of slurry. In the cases of low-permeability soil, appropriately increasing the content of slurry particles can improve the compactness of the filter cake.

The filter cake formation during slurry shield tunneling in high permeability soil layers is complex and difficult to monitor. There is no reliable method to evaluate the mechanical characteristics during the filter cake formation. A theoretical model is proposed to describe the filter cake formation and development in this study. The finite difference method is used to simulate the whole filter cake formation process. In addition, the influence of the key bentonite slurry parameters and of the deep infiltration on the filter cake formation is investigated based on the proposed model. The results show that the excess pore water pressure within the filter cake is not uniformly distributed. The slurry support effect is manifested by a pressure drop generated on both sides of the filter cake. The development process of the filter cake can be summarized into three stages: prior infiltration filling of the filter cake, accumulation and thickening of the new filter cake, and compression and consolidation of the prior filter cake. The slurry deep infiltration results reflected by the membrane specific resistance have the most significant effect on the filter cake development. Compared with the slurry concentration, the viscosity has a greater influence on the formation and final thickness of the filter cake.