Evaluation of Pullout Resistance of Reinforcing Strips Embedded in Cement Modified Marginal Backfill of Mechanically Stabilized Earth (MSE) Walls

Pull–out resistance of reinforcing materials is one of the internal stability criterions in Mechanically Stabilized Earth (MSE) construction. The pull–out resistance is normally calculated taking the friction coefficient equal to tan(δ); δ being the angle of internal friction in case of rigid reinforcing materials. For flexible/extensible reinforcing strips, the friction coefficient cannot be directly taken and in this direction, several attempts have been made by various researchers to evaluate suitable pull–out parameters. Further, the complexity increases within the use of marginal backfill soils wherever, suitable soils are not available. The present work is an effort to determine the pull–out parameters of different types of reinforcing materials embedded in marginal backfill soil without and with cement modification. The testing was carried out in laboratory using a test box and in the field by constructing model embankments. The pull–out factors F^* and α as suggested by FHWA were evaluated using the test data and compared them with those obtained using conventional sand backfill.