Abstract
In any projects involving the use or treatment of slurry clay, the shear strength, that is, the yield shear stress is an important parameter. Currently it is obtained indirectly through extrapolations of data from either viscometer or "vane-type" shear tests which have a number of shortcomings. A direct method which relies on the vertical penetration of a thin plate or a thin hollow cylinder under an incremental load is proposed in this paper. The yield shear stress mobilised at equilibrium is then obtained and compared with that from a series of viscometer tests. The very good agreement confirms the validity of the method which is easier to use and able to give the parameter directly. The rheology of the slurry clay is then studied and is found to be governed by a Bingham model at low strain rate and a power law model at higher strain rate. For different clays, when the yield shear stress is plotted against (water content/liquid limit), a unique relationship is obtained. Also there is a pronounced change at a limit of 2.0, below which the slurry becomes a paste. In this paper, this limit is termed the slurry limit.
