Stress-Dilatancy Behavior of Highly Elastic Rubber-Added Cohesionless Materials

Dilatancy is commonly defined as the ratio of the rates of plastic volumetric strain to plastic deviatoric strain, denoted as D^p. Owing to the high modulus of elasticity, the elastic volumetric and deviatoric strain rates under shear stress in conventional cohesionless materials are negligible. Therefore, using the ratio of the rates of total volumetric to deviatoric strain (D^t) as an approximation is common in studying stress-dilatancy behavior and calibrating dilatancy model parameters. This approach is also common in the study of rubber-added cohesionless materials (RCM). However, RCM with a common range of rubber content exhibit a significantly lower modulus of elasticity compared to conventional cohesionless materials. Further research is needed to evaluate the potential impact of elastic strain rates in RCM on stress-dilatancy analysis. Therefore, comparisons were conducted on the stress-dilatancy responses of a series of tests on RCM, where dilatancy is calculated by D^p and D^t, respectively. Furthermore, a modified method for calibrating the parameters of a state-dependent dilatancy model considering D^p is presented. It turns out that D^p is better suited and more precise for dilatancy analysis on highly elastic RCM. Additionally, the dilatancy model can more precisely capture the test results of RCM with parameters calibrated by the proposed method.