Model tests of the response of landslide-stabilizing piles to piles with different stiffness

The deformation characteristics of landslides, reinforced by piles having different stiffness, are examined using physical model tests. Taking the Majiagou landslide and its pile system as a real prototype, and using a model test bed with 57-cm-long test piles made of reinforced concrete and polyesteramide to simulate rigid and flexible piles, the displacements of two physical models were monitored during progressive loading to simulate the landslide-stabilizing pile system. The results indicate that (1) the bending moment of the rigid piles showed a reverse S pattern, peaking at the pile head; (2) the bending moment of the flexible piles developed a triangular pattern, peaking at the middle and lower parts of the pile; (3) the relative displacements of the landslide and piles during loading disclose four evolutionary stages, termed initial, coordinated, uncoordinated deformation, and failure; (4) the flexible pile system has a longer coordinated action stage but a shorter uncoordinated stage, than the system constructed with rigid piles. Finally, (5) the rigid piles exert an excellent control of soil deformation upslope of the piles, but it is easier for the landslide to slip over the pile heads. The results provide fundamental data for evaluating the long-term performance of the landslide-pile systems constructed with piles having different rigidity.