ABSTRACT
Porous flow is the expression used for flow through a granular medium, like sand, pebbles or stones. The loads due to porous flow often come from the soil side of the interface soil-water. As in open channel flow, pressures and velocities are related and both can be considered as loads. The flow through fine material, like clay or sand, is laminar for which the Forchheimer relation reduces to Darcy's law. In combination with the continuity equation, this can be translated, either graphically or numerically, into equipotential lines and streamlines. With this information about loads (pressures and velocities), the stability of various porous flow situations can be judged. For turbulent porous flow, as in rock, the knowledge is often still insufficient and empirical relations have to be used in design computations. Impervious protections have to withstand occurring pressures. Weight and friction are the parameters that determine the stability of protections without internal strength.
