Full-Scale Tests on Effects of Slope on Lateral Capacity of Piles Installed in Cohesive Soils

Abstract

A series of full-scale lateral load tests of fully instrumented piles in cohesive soils were carried out to assess the lateral response of piles in free-field and near a slope condition. The test piles were loaded laterally using a hydraulic actuator to observe load-displacement relationship at loading elevation, axial strain response, and rotation response. It was found that the proximity of slope significantly affects the maximum lateral load capacity of the piles, but not significantly when the piles are installed at 8D (where D is pile diameter) or greater from the slope crests. In addition, it was observed all the piles except the 0D pile resulted in similar initial stiffness for the load-displacement curves, and the piles closer to the slope showed less passive resistance at smaller displacement. Using the test records, p-y curves for each test pile were back-calculated. By normalizing the p-y curves for the piles near the slope with the ones on the level ground at any soil displacement and depth, the p-multipliers accounting for the slope effects in lateral load analysis are derived. Based on the calculated p-multipliers, it was found that effects of adjacent slope to lateral behaviors of piles can be explained as a function of soil displacements; the p-multipliers are larger at small soil displacements and vice-versa.