Citation
Structural capacity evaluation of drilled shaft foundations with defects

Material Information

Title:
Structural capacity evaluation of drilled shaft foundations with defects
Creator:
Haramy, Khamis Y
Publication Date:
Language:
English
Physical Description:
xxiii, 364 leaves : illustrations ; 28 cm

Subjects

Subjects / Keywords:
Shafts (Excavations) ( lcsh )
Boring -- Quality control ( lcsh )
Foundations -- Design and construction ( lcsh )
Genre:
bibliography ( marcgt )
theses ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
Includes bibliographical references (leaves 361-364).
General Note:
Department of Civil Engineering
Statement of Responsibility:
by Khamis Y. Haramy.

Record Information

Source Institution:
|University of Colorado Denver
Holding Location:
Auraria Library
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
71814690 ( OCLC )
ocm71814690
Classification:
LD1193.E53 2006m H37 ( lcc )

Full Text
STRUCTURAL CAPACITY EVALUATION OF DRILLED SHAFT
FOUNDATIONS WITH DEFECTS
Khamis Y. Haramy
B.S. Virginia Tech, 1979
A thesis submitted to the
University of Colorado at Denver
in partial fulfillment
of the requirements for the degree of
Master of Science
Civil Engineering
by
2006


This thesis for the Master of Science
degree by
Khamis Y. Haramy
has been approved
by
Dr. Brian T. Brady
Date


Haramy, Khamis Y. (M.S. Civil Engineering)
Structural Capacity Evaluation of Drilled Shaft Foundations with Defects
Thesis directed by Professor Nien Yin Chang
ABSTRACT
Drilled shafts have become very popular deep foundation supports. Drilled shafts can
be constructed in a wider range of ground conditions with less noise and vibration
than driven piles. Quality assurance (QA) and quality control (QC) of drilled shafts
has become a concern due to difficulties in locating defects and determining load
bearing capacity. Various non-destructive evaluation (NDE) techniques have been
developed to estimate the integrity of the concrete. While NDE techniques provide a
powerful tool and have been widely accepted, many variables and unknowns can
affect the measurement results. Results are more difficult to interpret, leading to
unnecessary litigation over shaft integrity. In addition, influences of surrounding
ground, stress states under different load conditions, and crack development during
concrete curing further complicate determination of shaft performance.
This study focuses on the load bearing capacity evaluation of drilled shafts under
various conditions by analysis methods and numerical models. The analysis is
approached first from identification of design criterion and construction procedures,
with a brief review of NDE techniques. The analysis method is based on principles
and theorems from engineering mechanics, geotechnical engineering, concrete
chemistry, and geophysical engineering. The analysis results are used as input to the
numerical analysis. The numerical model employed in this research is incorporated
into the Geostructural Analysis Package (GAP), combining the widely accepted
numerical methods of Discrete Element Method (DEM), Particle Flow Method
(PFM), Material Point Method (MPM), and Finite Differencing (FD), together with
engineering mechanics constitutive models, concrete chemistry models,


thermodynamics models, and geophysical tomography and holography for
geotechnical engineering application. GAP has been successfully used for ground
characterization in highway engineering and mining operations.
This study explores many concerns recently raised for drilled shaft design,
construction and maintenance. Recommendations and conclusions may provide
engineers with more information and a better understanding of drilled shaft
foundations to revolutionize foundation design, concrete mix design, construction
techniques, NDE measurement, and defect evaluation, to improve performance and
efficiency with reduced litigation risk.
This abstract accurately represents the content of the candidates thesis. 1 recommend
its publication.
Signed
Dr. Nien Yin Ch$ig


DEDICATION
I dedicate this thesis to my wife, Kathy Haramy, and my supervisor, Bob Welch, for
their unfaltering understanding and support while I was pursuing my masters degree
and writing this thesis.


ACKNOWLEDGMENT
I would like to acknowledge several persons who contributed to the completion of
this thesis. This research could not have been possible without the support and funds
from Mr. Roger Surdahl, the Technology Development Coordinator at the FHWA-
CFLHD, Mr. Alan Rock, Dr. Runing Zhang, and Dr. David Wilkinson for developing
the modeling programs that were used for the analysis. I would also like to thank Mr.
Frank Jalinoos and Ms. Natasa Mekic-Stall for their assistance in data collection. I
would also like to acknowledge the efforts of all the committee members for their
contributions, including Dr. Nien Yin Chang, Dr.Brian Brady, and Dr. Aziz Khan.


CONTENTS
Figures...................................................................xiii
Tables...................................................................xxiii
Chapter
1 Introduction...............................................................1
1.1 Purpose and Objectives...................................................5
1.2 Background-Drilled Shaft Foundations.....................................7
1.2.1 Description............................................................7
1.2.2 Advantages and Disadvantages..........................................12
1.2.3 Construction Inspection and Observation Methods.......................13
1.2.3.1 Down-Hole Inspections...............................................14
1.2.3.2 Probe Inspection....................................................14
1.2.3.3 Video Camera Inspection.............................................15
1.2.3.4 Shaft Wall Sampling and Rock Socket Wall Roughness Inspection.......16
1.2.3.5 Electro-Mechanical and Acoustic Shaft Caliper.......................17
1.3 NDE Methods for Determining Drilled Shaft Integrity.....................18
1.3.1 Overview..............................................................19
1.3.1.1 History of Non-Destructive Evaluation Methods.......................19
1.3.1.2 Summary of a National DOT Synthesis on Use of NDE Methods..........22
1.3.2 Sonic Echo and Impulse Response (SE and IR).........................25
1.3.2.1 Basic Theory and Procedures.........................................27
1.3.2.2 Applications/Limitations............................................29
1.3.2.3 Testing Equipment...................................................32
1.3.2.4 Defect Definition...................................................32
1.3.3 Gamma-Gamma Density Logging (GDL).....................................32
1.3.3.1 Basic Theory and Procedures.........................................32


1.3.3.2 Applications/Limitations.............................................33
1.3.3.3 Testing Equipment....................................................34
1.3.3.4 Defect Definition....................................................34
1.3.4 Crosshole Sonic Logging (CSL).......................................37
1.3.4.1 CSL Basic Theory.....................................................37
1.3.4.2 CSL Applications/Limitations.........................................43
1.3.4.3 CSL Testing Equipment................................................44
1.3.4.4 CSL Test Procedures and Results......................................53
1.3.5 Other Specialized Logging Methods.....................................57
1.3.5.1 Neutron Moisture Logging (NML).......................................57
1.3.5.2 Temperature Logging..................................................58
2 CSL Data Processing and Interpretation Using 3-D Tomography..............60
2.1 Basic Principles for 3-D Tomography......................................60
2.2 Case Studies............................................................63
2.2.1 Bridge Foundation Construction Site 1..................................64
2.2.1.1 CSL Test Procedures..................................................66
2.2.1.2 CSL Test Results and Analysis........................................71
2.2.1.3 Tomographic Imaging of the CSL Test Results.........................73
2.2.2 Bridge Foundation Construction Site 2.................................74
2.2.2.1 CSL Test Procedures..................................................78
2.2.2.2 CSL Test Results and Analysis........................................83
2.2.2.3 Tomographic Imaging of the CSL Test Results..........................85
2.2.2.4 Pile Repair Procedure................................................91
2.3 Tomographic Imaging Summary and Recommendations.........................99
3 Field Monitoring of Drilled Shaft Temperature, Velocity, Density, and Moisture 101
3.1 Temperature Monitoring..................................................101
3.1.1 Temperature Logging in Drilled Shaft 1 Abutment 1.....................102
3.1.2 Temperature Logging in Drilled Shaft 2-Pier 2.........................106
3.1.3 Temperature Monitoring With Thermocouples.............................109
viii


3.1.4 Temperature Monitoring Conclusion..................................Ill
3.2 Velocity Monitoring Results..........................................112
3.3 Density Monitoring...................................................115
3.4 Moisture Monitoring...................................................123
3.5 Summary of NDE Monitoring.............................................125
4 Concrete Defects and Curing Chemistry...................................128
4.1 Hydration Rates and Heat Generation during Concrete Curing............130
4.2 Curing Chemistry Modeling.............................................133
4.2.1 Empirical Modeling Methods...........................................134
4.2.2 Micro-Modeling Methods (M3)..........................................135
4.3 Thermal Issues for Concrete Construction in the Field.................136
4.3.1 General Aspects of Thermal Cracking Analyses........................137
4.3.2 Problems with the 20C Limit.........................................139
4.3.3 The Importance of Thermal Modeling in Concrete Structural Design and NDE
....................................................................140
4.4 Engineering Practice for Controlling Thermal Issues in Concrete Construction 141
4.4.1 Temperature Profiling................................................141
4.4.2 Simple and Practical Techniques for Reducing Thermal Concrete Cracking
With Standard Construction Techniques...............................142
4.4.2.1 Concrete Placement Temperature.....................................142
4.4.2.2 Aggregate Properties...............................................143
4.4.2.3 Cement Properties..................................................143
4.4.3 Field Measures to Reduce AT, Techniques and Implications..........145
4.4.3.1 Special Construction Measures......................................145
4.5 Comparative Evaluation of Thermal Control Measures....................146
4.6 Environmental Effects on Curing Chemistry and Concrete Quality........148
4.6.1 Changes in Ground Water Heat Conductivity..........................150
5 Numerical Modeling......................................................152
5.1 Establishment of Numerical Model.....................................153
5.2 Theoretical Models.....................................................154
IX


5.3 Thermal Modeling.......................................................155
5.4 Engineering Mechanics.................................................161
5.5 Discrete Element Method (DEM) Background.............................165
5.5.1 Discrete Element Method Definition...................................167
5.5.2 Equation of Motion...................................................168
5.5.3 Contact Mechanics....................................................171
5.5.3.1 Non-Linear Hertz-Mindlin Contact Model.............................172
5.5.3.2 The Visco-Elastic Contact Model....................................176
5.5.4 Validation of Numerical Models.......................................179
5.5.4.1 Energy Conservation................................................179
5.5.4.2 Damping and Dynamic Relaxation (DR) Tests.........................181
5.5.4.3 Wave Propagation...................................................183
6 Numerical Modeling Analysis of CSL in Drilled Shafts....................186
6.1 Geostructural Analysis Package (GAP) Model Description................186
6.2 Factors Affecting CSL Velocity Measurements...........................190
6.3 CSL Velocity Variations...............................................195
6.4 Effect of Surrounding Material on CSL Signals.........................195
6.5 CSL Wave Interaction with Rebar.......................................204
6.6 Tube Effects..........................................................212
6.6.1 Tube Material: PVC versus Steel Tubes...............................214
6.6.2 Tube Debonding.......................................................222
6.6.3 Sensor Drift within the Access Tubes.................................231
6.7 Concrete Cracking Effects.............................................238
6.7.1 Concrete Strength Reduction..........................................246
6.8 Honeycombs Effects....................................................247
6.9 Effect of Voids.......................................................255
7 Numerical Modeling of Concrete Curing...................................263
7.1 Empirical Curing Model Method........................................263
7.2 Curing Model Presentation.............................................266
x


7.3 Curing Model Simulation...............................................268
7.3.1 Compression..........................................................269
7.3.2 Cracking.............................................................276
7.3.3 Heat.................................................................282
7.3.4 Hydration............................................................286
7.3.5 Temperature..........................................................286
7.4 Discussion............................................................296
8 Numerical Testing of Axial Load Capacity of a Drilled Shaft with Anomalies.... 299
8.1 Axial Loading Model Analysis.........................................299
8.1.1 Displacement of 4 mm.................................................301
8.1.2 Displacement of 4 cm................................................304
8.1.3 Displacement of 8 cm.................................................307
8.1.4 Displacement of 12 cm................................................310
8.1.5 Displacement of 16 cm and 20 cm.....................................313
8.2 Load-Settlement Curve Analysis........................................313
8.2.1 Loosened Soil........................................................318
8.3 Discussion............................................................320
9 Summary, Conclusions, and Recommendations for Future Research..........323
9.1 Use and Interpretation of CSL Data..................................323
9.1.1 Effects of CSL Access Tubes..........................................323
9.1.2 The Potential of Numerical Modeling..................................324
9.1.3 Concrete Curing and Stress...........................................325
9.2 Suggestions for Improvements..........................................325
9.2.1 Use and Interpretation of CSL Data...................................325
9.2.2 Use of CSL Access Tubes..............................................325
9.2.3 Concrete Pouring.....................................................325
9.3 Suggestions for Future Direction.....................................326
xi


Appendix A............................................................327
Appendix B............................................................337
Appendix C............................................................341
References........................................................... 361
xii


FIGURES
Figure 1.1 Photo. 3m Diameter, 32m Deep Drilled Shaft Foundation for a Bridge
Structure Located at State Highway 19 over the Missouri River at Vermillion,
South Dakota...........................................................2
Figure 1.2 Schematic Diagram of a Typical Drilled Shaft Foundation............9
Figure 1.3 Photo Showing Drilled Shaft Construction..........................10
Figure 1.4 A Schematic Showing the CSL Setup.................................21
Figure 1.5 State DOT Survey Participants.....................................23
Figure 1.6 Map Showing the Responding State DOTs that Use NDE for QA/QC of
Drilled Shafts................................................................23
Figure 1.7 The Survey Results for the Question; Does your state DOT use NDE for
QA/QC of drilled shafts?.....................................................24
Figure 1.8 Survey Results for the Questions a) Which is the primary NDE method
your state uses for drilled shafts and b) What is the main reason your state
selects the primary NDE method?...............................................26
Figure 1.9 Sonic Echo and Impulse Response Equipment and Setup...............28
Figure 1.10 Sonic Echo Record and Depth Calculation..........................30
Figure 1.11 Depth Calculations Using Frequency Domain Data for the Impulse
Response Method.......................................................31
Figure 1.12 Gamma-Gamma Density Logging Equipment. (AMEC Earth &
Environmental, Inc.)..................................................35
Figure 1.13 Gamma-Gamma Density Logs and Results. (Geophysics, 2002).........36
Figure 1.14 Basic Wave Elements..............................................39
Figure 1.15 Freedom NDTPC Family of Instruments (Olson Engineering, Inc.)...47
Figure 1.16 PILELOGs Full Waveform Cross-hole Sonic Logging System
(InfraSeis, Inc.).....................................................50
Figure 1.17 PISA Pile Integrity Sonic Analyzer (Geosciences Testing and
Research, Inc.).......................................................52
Figure 1.18 (a) Full Waveform Stacked Traces (InfraSeis, Inc.) and (b) CSL Log Plot
-First Arrival Time (FAT), Apparent Velocity and Relative Energy Versus
Depth (GRL & Assoc., Inc.)....................................................55
Figure 1.19 Drilled Shaft with Defects.......................................56
xiii


Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
2.1 Pictures Showing Locations of (a) Boring B-5, (b) Boring B-6, and ( c)
Boring B-7..............................................................65
2.2 Schematic of Site 1 Bridge Plan and Subsurface Profile............67
2.3 Drilled Shaft, (a) Horizontal Cross-Section, (b) Vertical Cross-Section. 68
2.4 Drilled Shaft Installation and CSL Measurements...................70
2.5 3-D and 2-D Tomographic Representations of the A1-S2 Shaft Interior.
Green Represents Velocity Contours of Questionable Zones..............75
2.6 Schematic of Site 2 Bridge Plan and Subsurface Profile.............77
2.7 Drilled Shaft Details (a) Horizontal Cross-Section, (b) Vertical Cross-
Section.................................................................79
2.8 Variations in Apparent Velocity Due to Non-Uniform Tube Spacing.
CSL Log from CP4 between Tubes 2&3......................................83
2.9 (a) Initial CLS Test of the A2-4, (b) CSL Test of the A2-4 After 16 Days
of Curing...............................................................86
2.10 Difference Tomograms Between Pre- Grouting Test #2 and Pre-Grouting
Test #1 87
2.11 2-D and 3-D Tomographic Interpretation of the Geometry and
Location of the Defect at A2-4 ........................88
2.12 Location of the Coreholes and CSL Tubes of the A2-4............90
2.13 Coring Procedure of the A2-4 at Site # 2 Bridge................90
2.14 (a-c) Cores from the SE Core Hole (in Between CSL Tubes 2-3) and (d-
g) Cores from the Corehole in-between CSL Tubes 1-3 of the A2-4 Drilled
Shaft for Site 2 Bridge............................................92
2.15 Close-Up Look at the Defect with Velocity Reduction Counters (30% &
50% Reduction).......................................................93
2.16 Close-Up Look at the Defect with Velocity Reduction Counters (20%
Reduction and Combination of all)....................................94
2.17 (a) & (b) Mechanism Used for Pressure Grouting................96
2.18 Difference Tomograms in Between Post-Grouting Test and Pre-
Grouting Test #2 97
2.19 CSL Retest Results After Pressure Grouting.....................98
3.1 Temperature Monitoring of A1-SI at 6 hrs. (Black), 12 hrs. (Blue) and 24
hrs. (Red) after Concrete Placement.................................103
xiv


Figure 3.2 Temperature Monitoring of A1-SI at 6 hrs. (Black), 12 hrs. (Blue), 24 hrs.
(Red), 2 days (Green), 3 days (Purple), 4 days (Orange), 5 days (Teal), and 6
days (Yellow) after Concrete Placement..................................104
Figure 3.3 Temperature Monitoring of A1-SI Averaged from the 4 Access Tubes at
Depths of 3m (Black), 6 m (Blue), 9 m (Red), 12 m (Green), and 15 m
(Magenta)...............................................................105
Figure 3.4 Temperature Monitoring of P2-S2. Temperatures at 1 hr. (Black), 24 hrs.
(Red), 2 days (Green), 3 days (Purple), 4days (Orange), 5 days (Teal) and 6
days (Yellow) after Concrete Placement..................................107
Figure 3.5 Temperature Monitoring of P2-S2. Temperatures are Averaged from the
4 Access Tubes at depths of 0.8 m (Black, Gravel), 5 m (Blue, Clay), 10 m
(Red, Clay), and 12.5 m (Green, Shale Bedrock)....................108
Figure 3.6 Temperatures from Embedded Thermocouples of A2-S2- Red at the
Center of Shaft at 2.4 m, Blue Near Rebar Cage at Same Depth, and Green
Temperature Differential Between Both Stations.............110
Figure 3.7 Temperatures from Embedded Thermocouples of Shaft P-3 at Site 2 Near
Rebar Cage- Red at 3.66 m (Above Groundwater Table), Blue at 12.8 m
(Below Groundwater Table), and Green is Temperature Differential Between
Both Stations..........................................................111
Figure 3.8 CSL Velocity Measurements of Al-Sl- Velocities at 1 day (Red), 2 days
(Green), 3 days (Purple), 4 days (Orange), 5 days (Teal), and 6days (Yellow)
After Concrete Placement..........................................114
Figure 3.9 CSL Velocity Measurements of Al-Sl between Tubes 1-3 and 2-4 at 1
day (Red), 2days (Green), 3 days (Purple), 4 days (Orange), 5 days (Teal), and
6 days (Yellow) after Concrete Placement..........................116
Figure 3.10 Average CSL Velocity Measurements of A1 SI. Static Corrected
Velocity Values are Averaged from the 4 Access Tubes (and Six CSL Test
Paths) at Depths of 3m (Black), 6 m (Blue), 9 m (Red), 12 m (Green), and 15
m (Magenta).......................................................117
Figure 3.11 CSL Velocity Measurements of P2- S2- at 3 days (Purple) and 4 days
(Orange) After Concrete Placement.................................118
Figure 3.12 CSL Velocity Measurements of P2- S2- between Tubes 1-3 and 2-4 at 3
days (Purple) and 4 days (Orange) After Concrete Placement........119
Figure 3.13 GDL Density Monitoring of Al-Sl- with 1 day (Red), 2 days (Green), 3
days (Purple),and 4 days (Orange) After Concrete Placement..............120
xv


Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
3.14 Average GDL Density Monitoring of Al-Sl- Densities are Averaged
from the 4 Access Tubes at Depths of 3 m (Black), 6 m (Blue), 9 m (Red), 12
m (Green), and 15 m (Magenta)........................................121
3.15 GDL Density Monitoring of P2-S2. Densities at 1 day (Red), 2 days
(Green), 3 days (Purple), and 4 days (Orange) After Concrete Placement.. 122
3.16 NML Moisture Monitoring of Al-Sl- at 1 day (Red), 2 days (Green), 3
days (Purple), 4 days (Orange), 5 days (Teal), and 6 days (Yellow) After
Concrete Placement...................................................124
3.17 NML Moisture Monitoring of A1 -S1. Moisture Values are Averaged
from the 4 Access Tubes at Depths of 3 m (Black), 6 m (Blue), 9 m (Red), 12
m (Green), and 15 m (Magenta)........................................126
3.18 NML Moisture Monitoring of P2-S2- at 2 days (Green), 3 days (Purple),
and 4 days (Orange) After Concrete Placement.........................127
4.1 Typical Rate of Heat Evolution during Cement Hydration..........132
4.2 Temperature Plot from Data Progressively Collected from Access Tubes
142
5.1 2D and 3D Thermal Network Mesh for Heat Conducting Calculations 159
5.2 Visco-Elastic Contact Model for DEM................................167
5.3 Blocks in Contact..................................................169
5.4 Identical Elastic Rough Spheres in Contact.........................174
5.5 Hertz Contact of Solids of Revolution...............................175
5.6 Stack Balls Setup for Energy and Dynamic Relaxation Numerical Tests
...................................................................180
5.7 Total Energy of Stack Ball.....................................181
5.8 Dynamic Relaxation Test Results................................183
5.9 1-D P-Wave Propagation in a Rod................................185
6.1 Material Palettes used in GAP Models. Defects Shown in Red Include
Honeycombs, Cracking, and Debonding. Darker Colors on the Left Represent
Lower Values. These Palettes are used to Display Corresponding Velocity,
Wave Compression, Average Stress, Temperature, Heat Generation,
Hydration Phase, Tension Strength, Modulus, etc. A Cross-section of the 1 m
Drilled Shaft used in the Study is Shown on the Right. The Shaft is in the
Center, Surrounded by Dry Sand, Wet Sand, Clay, and Rock. Portions of the
xvi


Wet Sand, Clay, and Concrete are Hidden to Show the Internals of the Model.
......................................................................187
Figure 6.2 Location of Drilled Shaft Cross-section Surrounded by Rock........191
Figure 6.3 Location of 3D Section within Drilled Shaft.......................192
Figure 6.4 Rock (Top Left) vs. Clay (Top Right) at 20 ps, with Difference (Bottom)
..............................................................................196
Figure 6.5 Rock (Top Left) vs. Clay (Top Right) at 60 ps, with Difference (Bottom)
..............................................................................197
Figure 6.6 Rock (Top Left) vs. Clay (Top Right) at 120 ps, with Difference (Bottom)
..............................................................................198
Figure 6.7 Rock (Top Left) vs. Clay (Top Right) at 300 ps, with Difference (Bottom)
..............................................................................199
Figure 6.8 Rock (Top Left) vs. Clay (Top Right) at 500 ps, with Difference (Bottom)
.......................................................................200
Figure 6.9 CSL Signals from Rock vs. Clay, between Access Tubes 1 and 2 (Top),
and Tubes 1 and 3 (Bottom)............................................201
Figure 6.10 No Rebar (Top Left) vs. Rebar (Top Right) at 20 ps, with Difference
(Bottom)..............................................................206
Figure 6.11 No Rebar (Top Left) vs. Rebar (Top Right) at 20 ps, with Difference
(Bottom)..............................................................207
Figure 6.12 No Rebar (Top Left) vs. Rebar (Top Right) at 120 ps, with Difference
(Bottom)..............................................................208
Figure 6.13 No Rebar (Top Left) vs. Rebar (Top Right) at 300 ps, with Difference
(Bottom)..............................................................209
Figure 6.14 No Rebar (Top Left) vs. Rebar (Top Right) at 500 ps, with Difference
(Bottom)..............................................................210
Figure 6.15 CSL Signals from No Rebar vs. Rebar, between Access Tubes 1 and 2
(Top), and Tubes 1 and 3 (Bottom).....................................211
Figure 6.16 PVC (Top Left) vs. Steel (Top Right) Access Tubes at 20 ps, with
Difference (Bottom)...................................................215
Figure 6.17 PVC (Top Left) vs. Steel (Top Right) Access Tubes at 20 ps, with
Difference (Bottom)...................................................216
XVII


Figure 6.18 PVC (Top Left) vs. Steel (Top Right) Access Tubes at 120 ps, with
Difference (Bottom).................................................217
Figure 6.19 PVC (Top Left) vs. Steel (Top Right) Access Tubes at 300 ps, with
Difference (Bottom).................................................218
Figure 6.20 PVC (Top Left) vs. Steel (Top Right) Access Tubes at 500 ps, with
Difference (Bottom).................................................219
Figure 6.21 CSL Signals from PVC vs. Steel Access Tubes, between Tubes 1 and 2
(Top), and Tubes 1 and 3 (Bottom)....................................220
Figure 6.22 Tube Debonding (Top Left) vs. No Tube Debonding (Top Right) at 20
ps, with Difference (Bottom)........................................225
Figure 6.23 Debonding (Top Left) vs. No Tube Debonding (Top Right) at 20 ps,
with Difference (Bottom)............................................226
Figure 6.24 Debonding (Top Left) vs. No Tube Debonding (Top Right) at 120 ps,
with Difference (Bottom)............................................227
Figure 6.25 Debonding (Top Left) vs. No Tube Debonding (Top Right) at 300 ps,
with Difference (Bottom)............................................228
Figure 6.26 Debonding (Top Left) vs. No Tube Debonding (Top Right) at 500 ps,
with Difference (Bottom)............................................229
Figure 6.27 CSL Signals with Tube Debonding vs. No Tube Debonding, between
Access Tubes 1 and 2 (Top), and Tubes 1 and 3 (Bottom)..............230
Figure 6.28 Outside Sensor Drift (Top Left) vs. Inside Sensor Drift (Top Right) at 20
ps, with Difference (Bottom).........................................232
Figure 6.29 Outside Sensor Drift (Top Left) vs. Inside Sensor Drift (Top Right) at 20
ps, with Difference (Bottom).........................................233
Figure 6.30 Outside Sensor Drift (Top Left) vs. Inside Sensor Drift (Top Right) at
120 ps, with Difference (Bottom)....................................234
Figure 6.31 Outside Sensor Drift (Top Left) vs. Inside Sensor Drift (Top Right) at
300 ps, with Difference (Bottom)....................................235
Figure 6.32 Outside Sensor Drift (Top Left) vs. Inside Sensor Drift (Top Right) at
500 ps, with Difference (Bottom)....................................236
Figure 6.33 CSL Signals with Outside Sensor Drift vs. Inside Sensor Drift, between
Access Tubes 1 and 2 (Top), and Tubes 1 and 3 (Bottom)...............237
XVlll


Figure 6.34 Cracking Defect (Top Left) vs. No Defect (Top Right) at 20 ps, with
Difference (Bottom)...................................................240
Figure 6.35 Cracking Defect (Top Left) vs. No Defect (Top Right) at 20 ps, with
Difference (Bottom)...................................................241
Figure 6.36 Cracking Defect (Top Left) vs. No Defect (Top Right) at 120 ps, with
Difference (Bottom)...................................................242
Figure 6.37 Cracking Defect (Top Left) vs. No Defect (Top Right) at 300 ps, with
Difference (Bottom)...................................................243
Figure 6.38 Cracking Defect (Top Left) vs. No Defect (Top Right) at 500 ps, with
Difference (Bottom)...................................................244
Figure 6.39 CSL Signals with a Cracking Defect vs. No Defect, between Access
Tubes 1 and 2 (Top), and Tubes 1 and 3 (Bottom).......................245
Figure 6.40 Honeycomb Defect (Top Left) vs. No Defect (Top Right) at 20 ps, with
Difference (Bottom)..........................................................249
Figure 6.41 Honeycomb Defect (Top Left) vs. No Defect (Top Right) at 20 ps, with
Difference (Bottom)..........................................................250
Figure 6.42 Honeycomb Defect (Top Left) vs. No Defect (Top Right) at 120 ps, with
Difference (Bottom)..........................................................251
Figure 6.43 Honeycomb Defect (Top Left) vs. No Defect (Top Right) at 300 ps, with
Difference (Bottom)..........................................................252
Figure 6.44 Honeycomb Defect (Top Left) vs. No Defect (Top Right) at 500 ps, with
Difference (Bottom)..........................................................253
Figure 6.45 CSL Signals with a Honeycomb Defect vs. No Defect, between Access
Tubes 1 and 2 (Top), and Tubes 1 and 3 (Bottom)..............................254
Figure 6.46 Void Defect (Top Left) vs. No Defect (Top Right) at 20 ps, with
Difference (Bottom)...................................................257
Figure 6.47 Void Defect (Top Left) vs. No Defect (Top Right) at 20 ps, with
Difference (Bottom)...................................................258
Figure 6.48 Void Defect (Top Left) vs. No Defect (Top Right) at 120 ps, with
Difference (Bottom)...................................................259
Figure 6.49 Void Defect (Top Left) vs. No Defect (Top Right) at 300 ps, with
Difference (Bottom)...................................................260
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