GLOBAL INVERSION TECHNIQUE FOR GEOTECHNICAL ENGINEERING APPLICATIONS By KHIEM TAT TRAN A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2010 1 © 2010 Khiem Tat Tran 2 To my parents, whose lifetimes of hard work have made mine easier 3 ACKNOWLEDGMENTS First of all, I would like to express my sincere gratitude to my advisor, Dr. Dennis R. Hiltunen. His valuable support, encouragement, and guidance during my doctoral research were what made this possible. I have benefited tremendously from his experience and research methodology. He has provided for me not only his knowledge but also his kind consideration. I thank the other members of my committee, Dr. Reynaldo Roque, Dr. Michael McVay, and Dr. Ashok V. Kumar for their valuable comments and suggestions. I would like to thank my parents for encouraging my studies. I deeply thank my wife who has supported my decisions and the results of those decisions for the past few years, and my son who has given me emotion to overcome all difficulties of my studies. Lastly, I extend thanks to all of my friends who treated me like family. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...............................................................................................................4 LIST OF FIGURES .........................................................................................................................7 ABSTRACT...................................................................................................................................10 CHAPTER 1 INTRODUCTION ..................................................................................................................12 1.1 Problem Statement............................................................................................................12 1.2 Hypothesis ........................................................................................................................14 1.3 Objectives .........................................................................................................................14 1.4 Scope.................................................................................................................................14 1.5 Organization of Dissertation.............................................................................................15 2 SITE CHARACTERIZATION METHODS USING SEISMIC WAVES.............................17 2.1 Seismic Waves..................................................................................................................17 2.2 Site Characterization Methods Using Seismic Waves......................................................18 2.2.1 Goals of Seismic Wave Methods ...........................................................................18 2.2.2 Borehole Methods ..................................................................................................18 2.2.3 Surface Methods.....................................................................................................19 2.2.3.1 Methods using surface travel times..............................................................19 2.2.3.2 Methods using surface wave dispersion.......................................................20 2.3 Overview of the Surface Methods ....................................................................................21 2.3.1 Overview of Methods Using Surface Travel Times...............................................21 2.3.2 Overview of Methods Using Surface Wave Dispersion.........................................23 2.4 Limitations of the Standard Methods Using Seismic Waves ...........................................25 2.4.1 Limitations due to Insensitivity of Data .................................................................25 2.4.2 Limitations due to Local Inversion Techniques .....................................................26 2.5 Suggested Improvements..................................................................................................26 2.5.1 Improvements by Using Sensitive Data .................................................................26 2.5.2 Improvements by Employing Global Inversion Techniques..................................27 3 INVERSION OF FIRST-ARRIVAL TIMES USING SIMULATED ANNEALING...........33 3.1 Introduction.......................................................................................................................33 3.2 Methodology.....................................................................................................................34 3.2.1 Forward Modeling..................................................................................................34 3.2.2 Optimization Method..............................................................................................35 3.3 Applications......................................................................................................................37 3.3.1 Applications on Synthetic Data..............................................................................37 5 3.3.2 Applications on Real Test Data..............................................................................40 3.4 Conclusion for Chapter 3..................................................................................................47 4 INVERSION OF COMBINED BOREHOLE AND SURFACE TRAVEL TIMES..............56 4.1 Introduction.......................................................................................................................56 4.2 Inversion of Synthetic Data ..............................................................................................58 4.2.1 Synthetic Model 1...................................................................................................58 4.2.1 Synthetic Model 2...................................................................................................61 4.2.1 Synthetic Model 3...................................................................................................62 4.3 Inversion of Real Test Data ..............................................................................................63 4.3.1 Newberry Test Site.................................................................................................63 4.3.2 Ocala Test Site........................................................................................................65 4.4 Conclusion for Chapter 4..................................................................................................66 5 TWO-DIMENSIONAL INVERSION OF FULL WAVEFORMS USING SIMULATED ANNEALING.................................................................................................80 5.1 Introduction.......................................................................................................................80 5.2 Methodology.....................................................................................................................82 5.2.1 Forward Modeling..................................................................................................82 5.2.2 Optimization Method..............................................................................................86 5.3 Applications......................................................................................................................88 5.3.1 Applications on Synthetic Data..............................................................................88 5.3.1.1 One-dimensional synthetic models ..............................................................88 5.3.1.2 Two-dimensional synthetic models..............................................................91 5.3.2 Applications on Real Test Data..............................................................................95 5.3.2.1 TAMU test site.............................................................................................95 5.3.2.2 Newberry test site.........................................................................................97 5.4 Conclusion for Chapter 5................................................................................................100 6 CLOSURE ............................................................................................................................128 6.1 Summary of Findings .....................................................................................................128 6.1.1 Inversion Technique Using Travel Times ............................................................128 6.1.2 Inversion Technique Using Full Waveforms .......................................................129 6.2 Conclusions.....................................................................................................................130 6.3 Recommendations...........................................................................................................131 LIST OF REFERENCES.............................................................................................................132 BIOGRAPHICAL SKETCH .......................................................................................................135 6 LIST OF FIGURES Figure page 2-1 Particle motions associated with body waves and surface waves (from Bolt 1976) .........29 2-2 Bore-hole methods: a) cross-hole test and b) down-hole test (from Foti 2000) ................30 2-3 Seismic refraction tomography: a) test setup, b)