REFORMED CARMAN'S FILTRATION THEORY AND ITS APPLICATION TO FORCED WATER LOSS OF CLAYEY FLUID MUD

Abstract

To clarify the water loss mechanism of clayey fluid mud, one-dimensional forced water loss tests have been carried out. Based on the measurement of pore pressure and of water content within a specimen, it is concluded that the water loss is governed by the filtration mechanism. Although the theory of filtration was already proposed by Carman, the authors have formulated a simple theory on the basis of presently clarified mechanism. It is expressed by the variables familiar to soil engineers. New theory ignores the consolidation process which proceeds in a specimen, but a well-grounded method to take this effect into consideration is proposed. It is revealed that the theory should be applied only for the initial water content higher than a limit one. This limit water content is lower for the higher applied load. The theory promises that; 1) the water loss proceeds in direct proportion to the square root of time up to the time necessary to the sufficient water loss, 2) this time increases with the second power of the initial specimen's thickness, and 3) the specimen's thickness gives no influence on the water loss velocity. These theoretical predictions are all confirmed by test results.