Experimental Study on the Formation and Characteristics of Mud Filtration Cake in Large‐Diameter Slurry Shield Tunneling

Abstract

Multiple soil layers may be exposed simultaneously on the excavated surface of a large-diameter slurry shield. To study the formation and characteristics of mud filtration cake on the excavation surface during large-diameter slurry shield tunneling, penetration tests of mud slurries in different soils were carried out using a self-made device, and the microstructures of different mud filtration cakes were observed using scanning electron microscopy. The test results showed that there were three categories of filling forms for mud slurries permeating the soils: mud filtration cake, mud cake + permeation zone, and permeation zone; correspondingly, there were three types of filtration loss, which was mainly affected by the specific gravity of mud slurry. Finally, the porosity and the fractal dimension for the pore area of the mud filtration cake were calculated, and it is found that the fractal dimension of pore area is beneficial to classify the type of mud filtration cake.

New insight into the additives in preparation and reduction of shield slurry

“…The gradient of additive dosages mentioned above is guided by the actual engineering practices of SSS formulation. Considering that the content of residual additives in WSSS cannot exceed the content of additives when preparing SSS, the maximum dosages of bentonite, CMC, PACE, and PGS in Table 4 were set to 6.0%, 2.0%, 7.5%, and 16.0%, respectively 5 , 37 – 39 .…”

AHP‐FSE‐Based Risk Assessment and Mitigation for Slurry Balancing Shield Tunnel Construction

“…Similarly, reference [ 34 ] studied the effect of seawater intrusion on slurry and filter cake properties during shield construction of undersea tunnel by laboratory experiment. Besides, reference [ 35 ] studied the formation mechanism and mechanical properties of filter cake for large diameter shield excavation through microscopic experiments.…”