A continuum fluid-particle coupled piping model based on solute transport

The occurrence of piping failures in earth structures demonstrates the urgency and importance of studying piping. With this intention, a new piping model was developed in the framework of continuum mixture theory. Assuming that porous media are comprised of solid skeleton phase, fluid phase and fluidized fine particles phase, the fluidized fine particles phase is considered to be a special solute migrating with the fluid phase. The three phases interact while being constrained by the mass conservation equations of the three phases, and a sink term was introduced into the mass conservation equation of the solid skeleton phase to describe the erosion of fluidized fine particles, then a new continuum fluid-particle coupled piping model was established and validated. The validation indicates that the proposed model can predict the piping development of complicated structures under complex boundary and flow conditions, and reflect the dynamic changes of porosity, permeability and pore pressure in the evolution of piping.