Experimental Study on Interaction between Slurry and Soil on Excavation Face of Shield in Sand Stratum

Abstract

In sandy soil, the timely and effective formation of a filter cake is crucial for maintaining the stability of the excavated face during slurry shield tunnelling. Obtaining real-time information on slurry infiltration and particle migration is challenging, which greatly impacts the formation of the filter cake. Real-time monitoring of slurry infiltration and particle deposition is achieved through the use of electrical resistivity and pore water pressure measurements of the soil. It has been discovered that the primary pathway for slurry infiltration is inevitable in sandy soil, and it is crucial to take note of the persistent slurry leakage resulting from this situation in the shield excavation face. The distribution of slurry particle deposition is highly non-uniform in the penetration direction, with the maximum particle deposition occurring at the slurry-soil interface. However, this deposition is susceptible to disturbance from shield cutting tools, which can compromise the safety of the excavation face. Even if the particle size of the slurry is smaller than the pore size of the sand stratum, the slurry with higher viscosity can still form an internal filter cake. Furthermore, the research indicates that slurry infiltration can induce regular changes in soil electrical resistivity.