Determination of Water Storage and Permeability Functions for Oil Sands Tailings

Abstract

The paper describes how soil-water characteristic c urve, SWCC, tests can be conducted on high volume change materials and used in conjunction with an independe ntly measured shrinkage curves to provide the requi red unsaturated soil property functions for numerical s imulations of the drying process. The saturated-uns aturated soil property functions are used for modeling the d rying of oil sands tailings. A laboratory test proc edure was developed for the accurate measurement of the shrin kage behavior of oil sands tailings. A laboratory t est procedure for measuring and interpreting the shrink age curve results is also presented. A regression c urve-fitting analysis was used to obtain a closed-form equation for the shrinkage curve. The shrinkage curve result s are combined with the measured soil-water characteristi c curve and used to identify the “true” air-entry v alue and residual conditions for the oil sands tailings. The meaning of various forms for the SWCC is described along with a designation of the correct interpretation th at needs to be placed on the soil-water characteris tic curve when determining both the permeability function and the water storage function. The saturated coeffici ent of permeability is combined with the SWCC to compute the hydraulic properties for the oil sands tailings. The paper concludes with a description of the manner in which each of the unsaturated soil properties can be used for the numerical simulation of drying oil sands tailin gs.