ABSTRACT
Large flowage deformations and the hydraulic collapse of ground piping, which induces erosion, are induced by the permeation of water through the ground. This plays an important role in the destabilization of ground during floods, liquefaction, erosion and so forth. In order to analyze these phenomena more precisely, it is necessary to model progressive seepage failure in the soil. Some reports have found that interactions between all three phases-solid, liquid and gas-play important roles. In particular, Kodaka & Asaoka (1994) may be the first instance in which the importance of the dynamics of air bubbles in geoengineering was revealed. Furthermore, when the Tokai flooding disaster occurred in the Nagoya region on 11 September 2000, a man who witnessed the process of dike failure recounted his story in a newspaper, claiming that, after a crack generated on the dike’s surface, white bubbles of water blew out of the crack, and then the dike gradually failed for about three hours. In reality, this type of phenomena has been frequently witnessed for generations. The blowing air bubbles that precede seepage failure are called ‘‘frog blows bubbles’’ by elderly people. Terzaghi (1942) gives a definition and discussion of hydraulic failure without air bubbles.
