Measured Soil-Pile Interaction Pressures for Small-Diameter Laterally Loaded Pile in Loose Sand

The Soil-Structure Interaction (SSI) facility at Lafayette College, which was funded by the National Science Foundation, was recently used to investigate the soil-pile interaction for laterally loaded piles with the main focus on the interaction pressure between the pile and surrounding soil. A precast concrete pile, that was 101.6 mm in diameter and 1.17 m long, was reinforced with one No. 4 rebar (diameter = 12.7 mm) located at the center of the pile cross-section. The pile was instrumented with strain gauges along the length of the pile, displacement and tilt gauges at the point of loading, displacement sensors along the length of the pile, and thin pressure sensors wrapped around the pile. The soil, which was rained around the pile, was classified as well-graded sand. This paper focuses on measuring the soil-pile interaction pressure for a laterally loaded pile. The paper also describes the installation procedure, the soil properties, the measured pile force-displacement relationship and the measured strain along the length of the pile. Measured interaction pressures present the first step to develop the soil force-displacement relationship (i.e., the soil reaction or the p-y curve) based on direct measurements. The experiment described in this paper presents the initial effort of the research team, which will be followed by further experimental work focusing on the behavior of laterally loaded piles in soft soils.