Beneficial role of batter pile in slope under infinite uniform surcharge loading

Abstract

Batter pile is used to find a more effective way to stabilize the slope. Thus, these two questions “where is the optimal location of batter piles on earth slopes?” and “which inclination angle is most beneficial for pile in earth slopes?” arise. The numerical simulation was conducted to investigate the performance of slope reinforced by batter pile. The surcharge loading, inclination angle and pile location were varied while keeping geometry of the slope and the soil property constant. The surcharge loading was applied on the slope crest by steps. The inclination angle varied from 0° to 20°. The pile was placed at middle-down (MD), middle (MI), middle-upper (MU) and upper (UP) part of slope, respectively. A finite length of batter pile (10 m) was adopted, and the pile toe was free. Four series of numerical models were proceeded to search the optimum location and inclination angle for pile, one that provided maximum lateral resistance. By analyzing the slope deformation and pile bending moment, the effects of position and inclination angle of pile were determined. The following conclusions could be drawn: (1) The surcharge loading on the slope crest will influence the deformation of slope remarkably. Both the lateral displacement and settlement increases simultaneously with the raise of loading. (2) The lateral displacement and settlement of slope vary as the pile location moves from the crest to the toe. The slope of UP condition has the the minimum lateral displacement, following by MI, MD and MU condition. The ranking of settlement is same with the lateral displacement. That is to say, the UP condition is the best location for piled slope, followed by MI condition. (3) The batter pile is beneficial for slope engineering, which can not only reduce the deformation of slope, but also decrease the bending moment exerted on pile shaft. The inclination angle should be in a reasonable range, a relatively small inclination angle could not fully utilize the potential capacity of batter pile, while exaggerated inclination degree is not befitting for construction. The inclination angle of 15° is an optimal choice for batter pile in slope. (4) The inclination angle has mutual effect with the pile location, they should be considered synchronously. For comprehensive consideration, UP 10°, UP 15°, MI 15° and MI 20° are preferred options for the piled earth slope when subjected to surcharge loading.