THE HORIZONTAL AND VERTICAL PERMEABILITIES OF GRANULAR MATERIALS

Many drainage applications require a knowledge of the permeability in the horizontal as well as the vertical direction. The paper describes the development of a 300 mm diameter vertical permeameter which complements the existing DOT 300mm horizontal permeameter. Both are robust and suitable for testing compacted aggregates with a median size of 30mm. A series of tests generally gave much larger measured values in the horizontal permeameter than in the vertical permeameter. It is suggested that segregation is the most likely cause of this discrepancy. (A) For the covering abstract see IRRD 890992.