Pasternak Model for Oblique Pullout of Inextensible Reinforcement

An analysis is presented for evaluation of the pullout capacity of sheet reinforcement subjected to oblique pullout force considering that the subgrade soil is represented as a two-parameter linear-elastic Pasternak model and the reinforcement as inextensible. Use of the Pasternak model makes the oblique pullout analysis more realistic. The orientation of the reinforcement at the pullout end is found to be different from the direction of the pullout force and depends on the shear modulus of the subgrade soil. A parametric study is carried out to evaluate the effect of various factors, such as the modulus of the subgrade reaction, shear modulus of the subgrade, angle of interface shear resistance, and the obliquity of the pullout force on the magnitude and direction of the reinforcement force and the end displacement. For the first time, oblique pullout results have been compared with direct measurements of the reinforcement inclination in the vicinity of the failure surface available in the literature, and the experimental data compare well with the present analysis. Model tests on single and multiple sections of sheet and strip reinforcements are also performed to study the suitability and applicability of the present analysis in the design of reinforced soil walls.