Abstract
A stress-dilatancy relation of sand is proposed on the basis of the experimental fact that the principal stress axes and the principal strain increment axes rotate without complete coincidence with each other during monotonous increace of horizontal shear stress acting on a sample in a simple shear test. The inclination angle ψ of the major principal stress axis to the vertical direction is deduced from a simple relationship ; τ/σN=κtan ψ, which is derived from theoretical consideration (Oda and Konishi, 1974) and verified by Cole's experimental results. The value of κ is a material constant for a given sand which is dependent only on the interparticle friction angle. By using this relation, the principal stress parameters such as mean stress (σ1+σ3)/2 and maximum shear stress (σ1-σ3)/2 are easily deduced from the shear stress τ and the normal stress σN acting on the horizontal shear plane in a simple shear test or even in a direct shear test.
