Soil stress field around driven piles
Creators: name: Allard, Marie-Agnes
Publisher: name: California Institute of Technology
Year: 1989

description: 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.
description: PhD, 1990: PB 91 170084.

My sincere gratitude goes to the many whose guidance, encouragement, friendship and support sustained me throughout these years of graduate studies. I am also indebted to the U.S. National Science Foundation, Chevron Oil Field Research, Inc., Exxon, Unocal, Earth Technology, and the Earthquake Research Affiliates of the California Institute of Technology for their support of this research.

Thank you Professor R.F. Scott for your teaching and education during these years, for sharing your vast and rich experience and interests with me, for your trust and support in my work and for your friendship.

Thank you professors of Civil Engineering, Geology and Seismology for your enthusiasm and generosity in sharing with the students your insight and experience.

Thank you Robert for your invaluable help as a dedicated system manager of the Earthquake Engineering Research Laboratory computer, for developing this powerful data processing and analysis software package, SIG, that you always tailored with much kindness to my ever changing needs, for sustaining a constant interest, enthusiasm and source of advice through many challenging discussions, and for offering your friendship.

Thank you John and Brian for advising on or building centrifuge mechanical, electrical and electronic equipment and hardware parts.

Thank you Elmer and Marty for teaching me the ins and outs of the machine shop and for helping in the construction of many parts.

Thank you Sharon, Crista, Carmen and the whole staff of Thomas for your kind help towards a student ever lost in the CIT and TEX mazes.

Thank you to the GSC members, to the graduate office staff for working together to alleviate the hardships of Caltech student life.

Thank you to Eric, Sylvie, Maria-Luce and the many friends from Caltech and outside for your support in my work and life, for creating a warm-hearted, enriching and lively environment.

Thank you to my family, for giving me the possibility and encouraging me to pursue studies.

Thank you, Francois, for your love, strength and patience, for believing in something greater, for giving me freedom.
description: Accepted Version - SML9001.pdf