Low-Temperature Rheological Behavior of Submarine Mudflows

Abstract

Due to seawater intrusion, submarine sediments and slide masses routinely evolve into fluidized mudflows during long-distance migration and seriously endanger marine engineering facilities. However, few studies of the rheological properties of mudflows have considered the low-temperature seafloor environment and natural sediment properties. Hence, a series of rheology experiments of sediment samples from the northern South China Sea were performed. The apparent viscosity and shear stress of mudflows at 0.5°C were 36.3% higher than those at 22°C. In addition, at a given temperature, the apparent viscosity and shear stress of mudflows with a 90% water content are on average 24 times greater than those of mudflows with a 151.2% water content. The internal variation mechanism of mudflow rheological behaviors was well analyzed on the basis of Brownian motion and interparticle interactions. The Herschel-Bulkley model was employed to fit the test results, and equations of the yield stress and consistency factor were established by considering the temperature. Furthermore, the relationships between rheological parameters and water content conditions are thoroughly discussed. A rheological model that considers the temperature and water content is proposed, and the results provide scientific support for the assessment of mudflow migration ranges, sediment transport, and marine engineering design.