Simulation of effects of particle breakage on sliding surface friction for a hypothetical soil continuum moving on an in
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Zheng Chen I Siming He
Simulation of effects of particle breakage on sliding surface friction for a hypothetical soil continuum moving on an inclined plane
Abstract 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 longrunout 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. Keywords Landslide . Sliding surface weakening . Particle breakage . Numerical simulation Introduction Some of the large landslides are characterized by strong fluidity and long-runout distance. Some giant landslides can travel a very long distance and reach a significant runup height, and the motion speed can even reach 112–213 m/s (Evans 1989). Increasing the velocity of landslide generally weakens its sliding surface friction (Lucas et al. 2014). Rapid long-runout landslides (RLLs) can often lead to catastrophic accidents and serious damages to lives and properties. Predicting the motion of RLLs and quantitatively assessing their runout distances and risk regions are significant for landslide prevention and mitigation (Wang et al. 2019). The high-speed, low-resistance, and superfluidity properties of largescale landslides remain an intractable problem that has long intrigued the landslides academics. The mechanism and the construction of physics models have always been the hotspots of researchers (Goren and Aharonov 2007; He et al. 2015; Hungr and McDougall 2009; Iverson 1997; Pitman and Le 2005; Pudasaini and Miller 2013). RLLs occur generally for the reason of low frictional resistance on sliding surface. Therefore, various theories and models have been proposed to explain the mechanisms of sliding surface weakening, including dilatancy and erosion effects (Iverson and George 2015; Pailha and Pouliquen 2009), air lubrication model (Kent 1966), bottom excess pore water pressure model (Sassa 1988; Sassa et al. 2004), mechanical fluidization model (Davies et al. 1999), thermal effect (Erismann 1979; Vardoulakis 2000), thermo-hydro-mechanical coupling effect (Goren and Aharonov 2009; He et al. 2015; Vardoulakis 2002),
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