Simplified method for measuring the Duncan model parameters of gravel-mixed core materials by means of triaxial tests

A method is proposed that shortening the time of large scale triaxial draining shear tests on gravel-mixed core materials by reducing the content of fine grains. The characteristics of strength and deformation of gravel-mixed core materials depend on the coarse grains. It is found that fundamental features of stress and strain curves of soil specimens do not change even though appropriate fine grains are reduced. With the decreasing amount of fine grains, the drain velocity in triaxial tests is improved considerably. The relationship between the content of fine grains which are reduced and the permeability coefficient of soil specimens is derived. The procedure of large scale triaxial tests on gravel-mixed core materials and the way to obtain the Duncan model parameters are given.