ABSTRACT
Constitutive laws of soil define the mechanical behaviour of soil. They basically represent the non-linear stress-strain characteristics of soil and its strength. Constitutive laws are known to be function of the: physical properties of soil, moisture content and relative density, confining pressure, intermediate principal stress, strain rate, and stress history of soil. The influence of physical properties of granular soil particles characterized by shape, size and grading have been studied to a limited extent. The effect of strain rate on small samples of sand was investigated by Casagrande and Shannon, Skempton and Bishop, Prakash and Venkatesan, Whitman and Healey and Whitman. The rheological models are constructed in an intuitive way and the corresponding relationships between stress and strain are deduced and compared with the experimental observations. Details of splines and their mathematical properties are described by Schoenburg, Ahlberg et al. and Greville. Kondner's work compared very well with that Desai's spline functions.
