Soil-Pile Interaction for a Small Diameter Pile Embedded in Granular Soil Subjected to Passive Loading

Abstract

The soil-structure interaction of piles used to stabilize failing slopes (i.e., subjected to lateral soil movement known as passive piles) was experimentally investigated using a state-of-the-art soil-structure interaction facility. A 102-mm diameter, 1.58-m-long precast concrete pile was installed in well-graded sand. The pile was instrumented with displacement and tilt gauges at the pile head and strain gauges, a flexible shape acceleration array, and thin tactile pressure sheets along the pile length. Furthermore, the three-dimensional (3D) movements of the soil surface and the top of the pile were monitored using two stereo digital image correlation (DIC) systems. By monitoring the relative movement of the soil surface and pile top, the DIC systems track the progression of the soil-pile interaction that occurs as the lateral displacement of the soil increases. The use of advanced sensors allows simultaneous measurement of the pile lateral movement and the soil-pile interaction pressures along the pile length. The measured pressures indicate that the moving soil applies a linearly increasing pressure along the pile length above the sliding surface. Most importantly, the pile displacements and soil-pile interaction pressures along the pile length, which were measured directly, were used to develop the soil-pile interaction force versus displacement relationships (i.e., p-y curves) for the passive loading condition.