Stress-Strain Behaviour and Model Prediction of Reinforced Residul Soil

A study of the shear strength and deformation characteristics of unreinforced residual soil is presented. Direct shear testing was conducted using a computerized shear box apparatus with stress levels ranging between 0.05 to 0.40 MPa. Effects of nonwoven geotextile reinforcement, orientation of reinforcements and volume changes on the shear strength of soil composites were analyzed. For reinforced soil composites, it was observed that the shear and volume change behaviour is related to the degree of reinforcement orientation. It was also showed that the contraction or dilation properties of the unreinforced and reinforced soil composites are highly dependent on the stress levels. An elasto-plastic model with plastic hardening (load transfer model) was extended to incorporate cohesive soils. The model parameters were then used to predict the stress strain behaviour of unreinforced and reinforced soil. The results presented satisfactory agreement with experimental observations at higher stress levels