5. Conclusion
We develop a physics-driven model of interfacial friction for geomaterials. Our theoretical model characterizes the random contact process of the interface through porosity, which successfully captures the transition of mechanical behavior from microscopic asperities to the macroscopic friction interface. Our model reveals the velocity-dependent sliding friction behavior of these verified geomaterials and shows that the interparticle contact temperature has a more dominant role in velocity-dependent friction than the ambient temperature. The velocity-dependent friction behavior can attribute to the adjustment of stress state and property during high-velocity shearing. Meanwhile, the difference in directional and tangential activation energy can cause velocity-dependent strengthening or weakening effects for geomaterials. The saturation of geomaterials not only exhibits the lubrication effect but also shares part of the pore pressure, which contribute to the decrease in the friction coefficient. Thus, the permeability and fluid viscosity coefficients, which affect the water flow and distribution characteristics, also affect the coefficient of friction. These findings provide a further understanding of the physical mechanism how shear velocity affect the contact and sliding friction of geomaterials. It has important implications for geological hazard prediction, not only in landslides and earthquakes but also in glacial avalanches on earth, even sliding failure progresses on other planets.