On the behavior of fine mud suspensions

• DOI: 10.1007/bf00437302
• Publication Date: 2004-11-12T00:58:06Z
• Authors: P. Coussot; J. M. Piau
• Keywords: Herschel–Bulkley fluid

Flows of natural mud-water mixtures are of great interest for industrial and civil engineering. But there is still no general agreement about the methods for determining the main rheological characteristics of these systems. We propose here an accurate rheological study of some natural mud-water mixtures. We first discuss the possible effects of changing various parameters such as temperature, pH, electrolyte concentration, solid concentration, clay type. The behaviour of these muds appears to be very sensitive to most of these parameters and to be hardly predictable from a knowledge of their components. Then we show that a Herschel-Bulkley model fits steady flow experimental data very well for a very large range of shear rates. We also suggest physical explanations of this model in agreement with our observations of behaviour changes when some parameters change. The yield stress value of this model provides a good estimation of real yield stress which is a key parameter for mixture behaviour. These considerations are very useful to characterize, predict and compare various mud flows.<br/>On présente ici une étude du comportement en cisaillement simple de mélanges boueux fins naturels. De nombreuses difficultés expérimentales sont rencontrées lors de tests de rhéométrie avec ces fluides. On montre que ces mélanges sont fondamentalement des fluides à seuil et que leur thixotropie est peu apparente. La courbe d'écoulement peut être représentée par un modèle du type Herschel-Bulkley dans une large gamme de gradients de vitesse.<br/>