4.3. The effect of permeability and viscosity
The permeability coefficient and liquid viscosity can significantly
affect the frictional behavior of geomaterials as they determine water
distribution and flow characteristics in geological disasters.
Figure 5 shows the effect of permeability
coefficient and fluid viscosity on friction coefficient at different
velocities. The coefficient of friction decreases as the permeability
coefficient increases. This is because the larger permeability makes the
water flow more easily and widely in granular materials, such as loess,
which enhances the lubrication effect and reduces the force between
asperities. Similarly, fluid viscosity can hinder its flow and
widespread distribution in granular materials. Therefore, the
coefficient of friction increases with the coefficient of fluid
viscosity.