Abstract
The aim of this paper is to estimate the behavior of pore pressure and efective stress in a highly saturated permeable layer under the shock water pressure variation like the breaking waves. The vertical, one dimensional analytical solution of Biot's equation for the wave propagation is presented for the situation where the solid and fluid materials satisfy "dynamic compatible" relation.
　It is found that the decrement of effective stress in a permeable layer occures in order from its surface when the shock water pressure finishes and the most decreasing place comes near the surface with the decrement of hydraulic conductivity and the active time of the shock water pressure. The possibility of liquefaction by the shock water pressure variation is recognized.

【キーワード】：衝撃水圧，間隙水圧，有効応力，洗掘，液状化

*愛媛大学大学院連合農学研究科
United Graduate School of Agricultural Sciences, Ehime Univ.
**高知大学農学部
Faculty of Agriculture, Kochi Univ.