Numerical modeling of reinforced soil segmental retaining walls under real toe restraint conditions

The toe restraint has a significant effect on the behaviour of hard facing reinforced soil retaining walls (RSWs). A non-linear hyperbolic interface model is established based on shear stress-displacement curves from modular block-grading gravel interface shear tests. A 3.6 m-high polypropylene geogrid reinforced soil wall on rigid foundation is simulated under working stress conditions using FLAC incoperated with the interface model. The shear properties of the toe interface, the horizontal displacements of the wall facing and toe block as well as the loads carried by the toe and reinforcements are then analyzed. The results show that the shear stress-dispalcement curve of the toe interface exhibits concave during wall construction. The interface normal stress, interface shear stiffness and loads carried by the toe and reinforcements increase with the wall height during construction. When the wall is constructed up to 3.6 m in height, the interface normal stress is 1.7 times the self-weight of wall facing blocks and approximately 87% of the total loads are carried by the toe. The displacments of the wall facing and toe block increase apparently during the initial stage of wall construction due to less shear stiffness of the toe interface. Compared to the constant toe restraint stiffness used in the former laboratory tests and numerical modeling of RSWs, the hyperbolic interface model can better reflect shear properties of the toe and foundation soils.