PREDICTION OF SOIL STRENGTH FROM HYDROLOGIC AND MECHANICAL PROPERTIES
Cone penetration resistance (an index of soil strength) was found to be linearly dependent upon soil water tension within a limited range of tensions close to saturation. This relationship was established with data collected from three soil types in farmers’ fields located in the Lower Fraser Valley of British Columbia during late winter and spring over a 2-yr period. For the mineral soils the slope of the relationship was predicted quite well by a theoretically-based equation. The slope could not be predicted for an organic soil. Solution of the equation required a number of simplifying assumptions and direct measurement of the angle of shearing resistance, [Formula: see text]. This equation was integrated and the constant of integration, the value of which depended upon the particular depth intervals at which measurements of cone penetration were made, was replaced by the intercept from the empirical strength-tension relationship. In this way, a semi-empirical model was developed for the prediction of soil strength from soil water tension, or vice versa, for the mineral soils. Prediction for the organic soil could be carried out with the empirical relationship.