Critical State Line and State Parameter of Sand-Fines Mixtures

Abstract

Critical state line and state parameter have been proved to be an effective method to evaluate and predict the drained and undrained behaviors of sand. However, the existences of fines significantly affect the critical state and state parameter. To overcome this problem, the concept of critical sate line CSL, and state parameter ψ have been investigated with various fines contents in angular sand by processing some previous studies. Results indicated that there is a unique line CSL obtained with a specific fines content for various confining pressures and different initial global void ratios. An increasing in fines content increases the slope of CSL. The critical state line firstly moved down to a limited fines content of 50%, and then, it became to move up. For state parameter, the state parameter generally increased with an increase in fines content. In addition, the normalized shear stress significantly decreases with an increasing the state parameter.