Pullout Response of Inextensible Sheet Reinforcement Subject to Oblique End Force

The kinematics of failure of reinforced structures such as reinforced retaining walls, embankments, slopes, and grounds suggest that the failure surface intersects the reinforcement obliquely, thus causing an oblique pull to the reinforcement. In this paper, pullout resistance of sheet reinforcement is evaluated for the condition when the reinforcement is subjected to an oblique end force assuming a linear subgrade response and an inextensible reinforcement. At high obliquities of the end force, increase in friction resistance due to the downward component of the end force becomes high; however, the high obliquity also causes bending of the reinforcement which reduces the friction resistance and thus pullout occurs. Equilibrium equations are applied to the final deformed shape of the reinforcement after considering proper variation in normal stresses and friction resistance with the deformed shape. The horizontal component of the oblique pullout force is found to increase by over 50% of the pure axial pullout capacity of the reinforcement for a typical case of an obliquity of 60° and an angle of interface shearing resistance of 30°. The most important factors affecting the horizontal component of the pullout capacity are the obliquity of the end force and the interface angle of shearing resistance. A comparison of results with finite-element analysis of pullout tests and back-analysis of model test results on the reinforced wall suggests that the present model leads to a more rational and better prediction of pullout failures.