Estimation of Unsaturated Soil Properties Using a Knowledge-based System

The Soil-Water Characteristic Curve (SWCC) is an important soil function relating the water content of a soil to soil suction. Many unsaturated soil properties (or soil property functions) can be related to the water content versus suction relationship of a soil. Hydraulic conductivity, shear strength, chemical diffusivity, water storage, unfrozen volumetric water content, specific heat, and thermal conductivity are all functions of the Soil-Water Characteristic Curve. Considerable judgment is required to develop the relationship between soil property functions. The judgment rules can be enforced using a knowledge-based system based on observations and empirical relationships amongst soil property functions. A knowledge-based system was developed using a relational database management system (RDBMS) known as Microsoft’s Access database program. Access provided a suitable environment for combining the user interface, knowledge base, database, and query system. This system provides an estimate of the Soil-Water Characteristic Curve as well as the other unsaturated property functions using basic soil classification data such as the grain-size distribution, density and specific gravity. The system allows the estimation of many complex soil properties while reducing both time and cost requirements. 1 Graduate Student, Department of Civil Engineering, University of Saskatchewan, Saskatoon, Sask., Canada S7N 5A9 2 Professor of Civil Engineering, University of Saskatchewan, Saskatoon, Sask., Canada S7N 5A9