Simulation of effects of particle breakage on sliding surface friction for a hypothetical soil continuum moving on an inclined plane

Rapid long-runout landslide is a hot topic in the field of landslide researches. Many researchers have proposed different models and hypotheses to explain the superfluidity of long-runout landslides. In this paper, the mechanism of sliding surface weakening caused by particle breakage is studied. Particle breakage can not only cause the excess pore water pressure but also weaken the friction coefficient of the sliding surface. These two factors are both the causes of the superfluidity of the landslide induced by particle breakage. In addition, the evolutions of breakage potential and excess pore water pressure are coupled into landslide dynamic equations to simulate how the particle characteristics such as porosity, crushing hardness, and particle shape influence the landslide fluidity. During sliding process, the numerical results indicate that the breakage potential of sliding surface decreases nonlinearly with time, the excess pore water pressure generated by particle breakage increases first and then decreases nonlinearly, and the effective friction coefficient decreases nonlinearly with time and tends to a residual value.