Modelling of soil-water characteristic curve for diverse soils using soil suction parameters

Abstract

The application of unsaturated soil mechanics in geotechnical engineering problems relies on the construction of the soil-water characteristic curve (SWCC). The existing relationships for SWCC are presented in the form of fitting equations, which contain fitting coefficients rather than physically well-defined soil parameters linked to test data. Hence, two new formulations are developed to represent the SWCC, which only involve actual soil parameters related to the test data. In addition, a solution method is also proposed to achieve convergence to a single set of soil parameters for the same SWCC. One of these is a rectangular hyperbolic function, particularly developed for cohesive soils, whereas the other formulation is formed of an inversed power function useful for all soil types. Both formulations are defined in terms of saturated water content, residual water content, air-entry value and residual suction parameters, which can be obtained using SWCC test data. The proposed equations are employed for a large database collected from the literature including diverse soil types and testing procedures. The results indicate that both formulations provided adequate performance for the suction range they are used.