Centrifugal tests on slope reinforcement by anti-sliding piles modelling change of reservoir water level

Anti-sliding pile is one of the most effective measures for slope reinforcement. On the basis of centrifugal tests modeling the impoundment and cyclical change of water level in the Three Gorges Reservoir, this paper pays attention to the reinforcement mechanism of unstable reservoir slope by anti-sliding piles; and the corresponding test techniques of centrifuge modelling are introduced. A series of centrifuge tests including natural slopes and reinforced slopes with different pile layouts are conducted; slope displacement, failure modes and bending moments of piles are obtained during the testing procedure; the distribution of landslide pushing force, mechanism of pile-slope interaction and arching effect are discussed as well. Results indicate that the deformation of reinforced slope will still occur during the first stage of change of reservoir water level; it will be gradually controlled during the form of arching effect due to different soil displacements behind the piles. Moreover, the bigger the pile spacing is, the weaker reinforced effects are, which leads to the larger slope deformation. However, the maximum pile bending moment of each test shows parabolic character, so there must exist an optimal pile spacing under which the reinforcing effect will be the best. In addition, the pushing force acted on the anti-sliding pile obeys multi-triangle configuration. This study provides not only the direct data for the investigation of interaction mechanism between pile and slope, but also the new idea of optimal pile spacing for slope reinforcement design. It will contribute a lot to the theory of slope stabilization by piles and prevention of landslide disaster in the Three Gorges Reservoir area.