Centrifuge Tests of Superlarge-Diameter Rock-Socketed Piles and Their Bearing Characteristics

Abstract

To understand the mechanical properties of superlarge-diameter piles in complicated geologic conditions, the authors carried out centrifuge model tests that simulated the bearing characteristics of single rock-socketed piles that had different cover thicknesses and rock-socket lengths. Valuable results were obtained from the centrifuge model tests. The overlying stratum of a single superlarge-diameter rock-socketed pile shares a certain proportion of the upper load, so it is not wise to neglect its bearing capacity in this type of design. The shaft resistance and tip resistance did not work synchronously with an increase in the upper load. Shaft resistance was mobilized prior to tip resistance and carried the majority of the upper load when the rock-socket length exceeded three times the pile diameter. There is an optimal rock-socket length for a certain thickness of overlying stratum. A centrifuge test was performed to investigate the behavior of a pile group socketed in bedrock with an inclined surface. The load distribution in the pile group was not even, and piles that had longer rock-socket lengths shared more load than piles that had shorter rock-socket lengths. The inclined surface caused differential settlement under concentrated vertical loading, which might result in safety issues with the superstructure.