Slurry flow and its infiltration behavior in sand stratum based on slurry fluid properties

Bentonite slurry is readily available, and extensively used in underground construction, where the in-situ infiltration behavior of the slurry is of great interest. As a solid–liquid biphasic fluid, slurry exhibits distinct fluid properties that set it apart from pure water. These unique properties play a significant role in determining its infiltration behavior during construction, making it a critical factor that cannot be overlooked. In this study, slurry shear tests were carried out using a rotational viscometer to characterize its fluid properties, and constant water head infiltration tests were conducted by a self-designed infiltration device to investigate the infiltration behavior of slurry in sand stratum. In addition, theoretical derivation based on the pipe flow was implemented to simulate the slurry flow in the stratum. The results show that, as the slurry infiltration continues, the relationship between the yield stress and initial hydraulic gradient experienced a “nonlinear to linear” process. The nonlinearity at the early stage of slurry infiltration is related to the evolution of the core phase of the slurry, which is the root cause of the nonlinear evolution of the fluid property and infiltration curves. A predicted relation between the fluid parameters of the slurry and its multiphase infiltration behavior was established, which are able to give a better understanding of the slurry behavior in engineering design.