Effects of Internal Erosion on Parameters of Subloading Cam-Clay Model

Internal erosion is widely detected in both natural deposits and earthen structures and potentially causes severe disasters. Suffusion is one of the modes of internal erosion in which fine particles in the soil are washed out along with water flow through pores formed by coarse particles. Mechanical consequences of internal erosion, specifically, suffusion, are not well investigated in term of constitutive modeling. Also, most of the present constitutive models concerning suffusion are validated by DEM simulations, not by actual soil response observed in soil tests. In this paper, triaxial seepage tests followed by drained compression on soil with 35% initial fines content under 50 kPa, 100 kPa and 200 kPa mean stresses are studied to investigate the applicability of the existing soil model to internally eroded soils. The subloading Cam-clay model is used to simulate the mechanical behavior of eroded soils. After confirming that the model can capture key features of uneroded specimens, the evolution of model parameters with erosion is examined by back analysis of the eroded specimens. From the simulation on the eroded specimens, evolutions of the slope of normal compression line and initial stress ratio with erosion are quantified. The changes of model parameters with erosion provide a useful reference for investigating the mechanical behaviour of granular materials subjected to suffusion.