Soil Stress Field Around Driven Piles

Citation

Allard, Marie-Agnès (1990) Soil Stress Field Around Driven Piles. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/GGE1-GC92. https://resolver.caltech.edu/CaltechETD:etd-02212007-130942

Abstract

The description, equipment, and results of a series of pile-driving experiments conducted in a centrifuge using a model pile driven in dry sand are presented.

The work was conceived on the basis of the modelling of a soil-structure system under an artificially generated gravitational field, and motivated by the need for experimental data for a better understanding of the complex phenomena involved in the pile-soil interaction during driving. The behavior of the pile itself has been the focus of more attention in the past, but few full-scale or model experimental results have been obtained to the present concerning the soil stress field during pile driving. These are necessary for comparison with analytical and theoretical work. The work presented here appears to be the first attempt to obtain dynamic response of the soil during driving. The objective was to obtain a good understanding of the physical phenomena occurring in the soil and pile during driving.

In order to achieve these objectives both dynamic (transient) and static responses of the soil and pile were measured by means of transducers: accelerometers and strain gages for the pile, pressure transducers for the soil. In particular, the relations between static and dynamic data were explored, which resulted in the modelling of the soil-transducer interaction with a non-linear, history-dependent, model.

Results were obtained regarding pile dynamics, soil dynamics, and soil stress field (radial and vertical distribution, stress contours). Both linear and soil-cell model assumptions were used, which enabled a comparison between the two, leading to an estimate that each constitutes a bound of the real stress field, with the linear giving the higher, and the non-linear the lower bound, and the true stress being closer to the lower bound.

The soil response during driving is obtained, filling the gap in the study of the pile-soil system, where only the pile response was known. Recommendations for further work and better experimental procedures are given.

Thesis Files