Pore-water pressure of debris flows

Until now, the pore water pressure, which is one of the stress constituents governing the flow characteristics of a steady, laminar debris flow, has been considered to be hydrostatic. We succeeded in measuring the pore water pressure distribution in solid-water phase flows with a rolling mill. The experimental results show that the pore water pressure actually exceeds the hydrostatic pressure, and indicates that the excess pore water pressure arises as a consequence of Reynolds stresses due to the shearing of interstitial water. (C) 2000 Elsevier Science Ltd. All rights reserved.