Micromechanical modeling for behavior of silty sand with influence of fine content

Silty sand is a soil mixture with coarse grains and fine grains. Experimental observations have shown that small amount of fines may reduce the undrained shear strength significantly. The purpose of this paper is to propose a micromechanical model for the stress–strain behavior of silty sand influenced by fines under drained and undrained conditions. The micromechanical stress–strain model accounts for the influence of fines on the density state of the soil mixture, thus consequently affect the critical state friction angle and the amount of sliding between particles. The present model is examined by simulating typical drained and undrained tests in conventional triaxial conditions. The simulated stress–strain curves are compared with the measured results on samples made of Ottawa sand and Foundry sand with various amounts of fines. The predictive ability of the present model for simulating the behavior of silty sand is discussed.