HYSTERESIS OF PORE WATER IN GRANULAR POROUS BODIES

EXPERIMENTAL DATA ARE REPORTED CONCERNING THE HYSTERESIS BEHAVIOR OF POROUS BODIES OF A SUBSTANTIAL MASS MADE UP OF SAND GRAINS AND RESULTS ARE COMPARED WITH PREDICTIONS OF THE INDEPENDENT DOMAIN CONCEPT. TUBE COLUMNS OF MATERIAL ARE USED AND THE GEOMETRY STABILIZED BY OVERBURDEN PRESSURE. THE DYNAMIC METHOD UTILIZES THE FACT THAT A SUFFICIENTLY LONG COLUMN OF A POROUS MATERIAL DRAINING TO A STATIONARY WATER TABLE ATTAINS IN ITS UPPER PART A STATE OF UNIFORM MOISTURE CONTENT AND A SUCTION WHEN SUBJECTED TO INFILTRATION AT ITS UPPER END AT A CONSTANT RATE. THIS CONSTANT FLOW RATE EQUALS THE HYDRAULIC CONDUCTIVITY OF THE POROUS BODY AT THE GIVEN MOISTURE CONTENT AND SUCTION. SOME EXPERIMENTAL RESULTS CONCERNING THE HYSTERESIS OF THE HYDRAULIC CONDUCTIVITY ARE REPORTED.