Uplift behavior of plates embedded in fiber-reinforced cement stabilized backfill

A series of pullout tests is presented in this manuscript and is used to identify the uplift response and the kinematics of failure of circular plates embedded in fiber-reinforced cement stabilized backfill layers at distinct normalized embedment depths (H/D), where H is the thickness of the treated layer and D is the diameter of the plates. Experimental results show that the uplift capacity of plates embedded in cement stabilizes backfill layers increases after the insertion of 0.5% fibers on the backfilled material. The addition of fibers to the cement stabilized backfill leads to an increase in uplift capacity of 43.5% for an H/D ratio of 1.0 and of about 20% for an H/D ratio of 2.0. Distinct load-displacement behavior were observed for plates embedded in both cement stabilized backfills and fiber-reinforced cement stabilized backfills: (a) pullout of plates in cement stabilized backfills at H/D ratios ranging from 1.0 to 2.0 exhibit a stiff elastic response until about 90% of the final uplift failure load, yielding just prior to brittle failure (which occurred at displacements smaller than 1 mm), after which, the pullout capacity dropped; (b) pullout of plates in fiber-reinforced cement stabilized backfills at H/D ratios ranging from 1.0 to 2.0 reveal a stiff elastic behavior until about 50% of the maximum uplift load, when fiber-reinforced cement stabilized backfill layers demonstrated the ability to continue to increase strength with ongoing deformation, suggesting the behavior of a ductile material until the end of testing at displacements of about 10 mm.