In this research work, a comprehensive testing program has been carried out to study the stress-strain and volume change behavior of unreinforced and reinforced residual soil. A series of drained triaxial tests were conducted using computer controlled GDS triaxial apparatus for unreinforced and reinforced soil. Test results show that reinforced soils exhibit higher failure strains and volume contraction than unreinforced soils. Reinforced soils with non-woven geotextile exhibit higher failure strains, strength and coefficient of interface friction than woven geotextile reinforced residual soil. A simplified approach for numerical calculations were proposed to predict the shear strength of unreinforced and reinforced soils for triaxial compression stress paths and the coefficient of interface friction for reinforced soils. Charts were also presented to predict the strength of reinforced soil and to determine the coefficient of interface friction from triaxial tests. Predictions of failure stress using simplified approach are satisfactory compared to laboratory observations.