One of the major difficulties in predicting the axial capacity of pipe piles in sand has resulted from a lack of understanding of the physical processes which control the behavior of piles during installation and loading. The objective of this research is to develop the experimental facilities necessary to identify these processes. A second goal of this dissertation is to perform load tests to study the phenomenon of pile plugging. This investigation uses methods that are fundamentally different from previous experimental studies, in a number of ways. First, an instrumented double-walled pile is used to delineate the frictional stresses acting against the external and internal surfaces of the pile. Miniature pore-pressure transducers were developed to fit between the pile walls. Second, a fast automatic laboratory pile hammer is used. The hammer is capable of representing the phenomena which occur during pile driving. Third, a data acquisition system which is capable of collecting data at a scale that has never been accomplished in foundation engineering in terms of the combined number of channels and sampling rate was built. Fourth, this study is the first to provide continuous measurement of the elevation of the soil inside the pile during installation and loading. Fifth, a pressure chamber; feedback control system; loading frame; sand handling, pluviating, saturating, and drying apparatus have been integrated to allow convenient load testing of piles under simulated field conditions. The results of this testing program validate the performance of the developed apparatus, and provide unique insights into soil-structure interaction during pile driving and subsequent loading. The measurements include dynamic and static excess pore pressures in sand, residual stress in the pile, and separate skin friction distributions inside the plug and outside the pile. The load tests were focused on identifying the effects of inertia and build-up of pore water pressure on pile plugging. The results of these tests contribute to a better understanding of pile behavior.
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