Scholars' Mine Doctoral Dissertations Student Theses and Dissertations 2009 Analysis using surface wave methods to detect shallow manmade tunnels Niklas Henry Putnam Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Geological Engineering Commons Department: Geosciences and Geological and Petroleum Engineering Recommended Citation Putnam, Niklas Henry, "Analysis using surface wave methods to detect shallow manmade tunnels" (2009). Doctoral Dissertations. 2134. https://scholarsmine.mst.edu/doctoral_dissertations/2134 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. ANALYSIS USING SURFACE WAVE METHODS TO DETECT SHALLOW MANMADE TUNNELS by NIKLAS HENRY PUTNAM A DISSERTATION Presented to the Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE & TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in GEOLOGICAL ENGINEERING 2009 Approved by Neil L. Anderson, Co-Advisor J. David Rogers, Co-Advisor Jeffrey D. Cawlfield Michael J. Shore Neill P. Symons Steve L. Grant iii ABSTRACT Multi-method seismic surface wave approach was used to locate and estimate the dimensions of shallow horizontally-oriented cylindrical voids or manmade tunnels. The primary analytical methods employed were Attenuation Analysis of Rayleigh Waves (AARW), Surface Wave Common Offset (SWCO), and Spiking Filter (SF). Surface wave data were acquired at six study sites using a towed 24-channel land streamer and elastic-band accelerated weight-drop seismic source. Each site was underlain by one tunnel, nominally 1 meter in diameter and depth. The acquired surface wave data were analyzed automatically. Then interpretations compared to the field measurements to ascertain the degree of accuracy. The purpose of this research is to analyze the field response of Rayleigh waves to the presence of shallow tunnels. The SF technique used the variation of seismic signal response along a geophone array to determine void presence in the subsurface. The AARW technique was expanded for practical application, as suggested by Nasseri (2006), in order to indirectly estimate void location using a Normalized Energy Distance (NED) parameter for vertical tunnel dimension measurements and normalized Cumulative Logarithmic Decrement (CALD) values for horizontal tunnel dimension measurements. Confidence in tunnel detects is presented as a measure of NED signal strength. Conversely, false positives are reduced by AARW through analysis of sub-array data. The development of such estimations is a promising tool for engineers that require quantitative measurements of manmade tunnels in the shallow subsurface. iv ACKNOWLEDGMENTS I would like to thank my committee, Dr. Neil L. Anderson, Dr. J. David Rogers, Dr. Jeffery D. Cawlfield, Dr. Michael J. Shore, Dr. Neill P. Symons, and Dr. Steven L. Grant. I am indebted to Dr. Ali Moghaddam- Nasseri and Dr. Peng Xie for their direct contribution of the AARW method. Dr. Steven Grant and his graduate students, Mr. Pretam Modur and Mr. Colin Stagner from the Electrical Engineering Department, deserve full credit for designing the Spiking Filter and integrating the algorithms into the Demonstration Mobile Seismic Unit software suite. Mr. Oleg Kovin and Mr. Evginey Torgashov patiently assisted me in gathering and processing the volumes of seismic field data used in this work. Collaboration by Dr. Giovanne Cacante (University of Waterloo, Canada) and by Dr. Jianghai Xia and Dr. Miller (Kansas Geological Survey) were instrumental in providing additional background information. I appreciate the administrative support and professionalism shown by the Geological Sciences and Engineering Department, including Ms. Katherine Mattison and Ms. Paula Cochran. This work was made possible by funding from the Leonard Wood Institute (LWI61042) on behalf of the U. S. Army Research Laboratory. Mr. Stephen Tupper, Mr. Dorsey Newcomb, Mr. Joe Driskill, and Mr. Bob Chapman's flexibility during the research were greatly appreciated. I dedicated this dissertation to my father CW3 (Retired) Richard L. Putnam and mother Britta Deloris Stassfurth Putnam. My spouse, Silvia has given graciously of her patience and time throughout my studies. v TABLE OF CONTENTS Page ABSTRACT ....................................................................................................................... iii ACKNOWLEDGMENTS ................................................................................................. iv LIST OF ILLUSTRATIONS ........................................................................................... viii LIST OF TABLES ............................................................................................................ xii NOMENCLATURE ........................................................................................................ xiii SECTION 1. INTRODUCTION ...................................................................................................... 1 1.1. PROBLEM STATEMENT ................................................................................. 1 1.2. STUDY AREA: SIX TEST SITES..................................................................... 2 1.3. RESEARCH OBJECTIVES AND METHODOLOGY ..................................... 3 1.4. RESEARCH SIGNIFICANCE ........................................................................... 4 1.5. ORGANIZATION OF DISSERTATION .......................................................... 4 2. MECHANICAL WAVE PROPAGATION THEORY .............................................. 6 2.1. SEISMIC WAVE PROPAGATION IN ELASTIC MEDIA .............................. 6 2.1.1. Elastic Waves ........................................................................................... 6 2.1.2. Elastic Wave Equations ............................................................................ 8 2.1.3. Dispersion Curves, Group and Phase Velocity ...................................... 11 2.1.4. Characteristic and Behavior ................................................................... 12 2.1.5. Damping and Attenuation of Rayleigh Waves ....................................... 13 2.2. SIGNAL PROCESSING .................................................................................. 14 2.2.1. Time Domain Analysis ........................................................................... 15 2.2.2. Frequency Domain and Fourier Transform ............................................ 17 2.2.3. Inversion of Surface (Rayleigh) Wave Data .......................................... 18 3. APPLIED GEOPHYSICAL METHODS ................................................................ 22 3.1. COMMON SHOT DATA ................................................................................. 22 3.2. SURFACE WAVE COMMON OFFSET (SWCO) ......................................... 26 3.3. SPIKING FILTER (SF) .................................................................................... 28 3.4. ATTENUATION ANALYSIS OF RAYLEIGH WAVES (AARW) ............... 32 vi 3.4.1. Characteristic Wavelength ..................................................................... 34 3.4.2. Normalized Energy Distance (NED) ...................................................... 34 3.4.3. Cumulative Amplified Logarithmic Decrement (CALD) ...................... 36 3.4.4. Depth and Diameter Limits .................................................................... 39 3.5. COMPLEMENTARY METHODS .................................................................. 41 3.5.1. Ground Penetrating Radar (GPR) ........................................................... 42 3.5.2. Resistivity ............................................................................................... 45 3.5.3. MASW Shear Wave Vertical Profiles .................................................... 47 4. OVERVIEW OF FIELD AQUISITION PARAMETERS ....................................... 54 4.1. GEOPHONE SELECTION & CALIBRATION .............................................. 54 4.1.1. Natural Frequency .................................................................................. 54 4.1.2. Acceptable Geophone Deviation for AARW ......................................... 56 4.2. STREAMER ARRAY ...................................................................................... 61 4.3. SEISMIC IMPACT SOURCE .......................................................................... 63 4.4. DATA AQUISITION SETTINGS ................................................................... 68 5. FIELD MEASUREMENTS AND COMPLEMENTARY GEOPHYSICAL METHODS ............................................................................................................... 70 5.1. DATA ACQUISITION ..................................................................................... 70 5.1.1. Sites with Soil-Covered Surfaces ........................................................... 71 5.1.1.1. Interpretation of MASW data ....................................................72 5.1.1.2. Interpretation of resistivity data .................................................72 5.1.2. Sites with Paved Surfaces ...................................................................... 74 5.1.2.1. Interpretation of MASW data ...................................................78