Centrifuge modeling on reinforced soil segmental retaining walls under different toe restraint conditions

The centrifugal model tests are performed on four reinforced soil segmental retaining walls under different toe restraint conditions, which are normal toe restraint, smoothing the block-pad interface, smoothing the pad-foundation interface, smoothing the pad-foundation interface and then excavating the foundation soils in the front of the leveling pad. The influences of the toe restraint condition on the internal stability of reinforced segmental wall under working stress are discussed. The test results show that the toe restraint conditions significantly affect the internal stability of reinforced soil segmental walls. For the wall that the block-pad interface is smoothed, the bottom block slides along the block-pad interface, which leads to an obvious increase in the horizontal displacements and reinforcement strains within the middle and lower parts of the wall and a triangular distribution with height of connection loads between reinforcements and facing. For the wall with the pad-foundation interface smoothed, the foundation soils in the front of leveling pad can provide the pad with enough restraint, thus the internal stability of the wall is the same as that under the normal toe restraint. The purpose of smoothing the pad-foundation interface and then excavating the foundation soils in the front of the leveling pad is to simulate the condition that the toe is scoured. In such condition, the pad slides along its interface with the foundation soils, the facing displacements and the reinforcement strains within the middle and bottom parts of the wall increase significantly, and the connection loads in reinforcements are close to the maximum reinforcement loads under the limit state calculated by the AASHTO method, but the wall still remains stable. In the extreme situation where the toe is eroded by scouring, the effect of toe constraint should not be considered in the design of the reinforced soil segmental retaining walls. For the walls under working stress, the reinforcement loads can be calculated using the K-stiffness method with consideration of the toe restraint effects.