Ground Penetrating Radar: Theory and Practice is a practical guide to using this powerful underground surveying technique. The author uses her wide experience to explain the critical factors in using GPR and how parameters, such as wavelength, attenuation and loss need to be properly considered to obtain good survey results.
The first chapter introduces the underlying physics and explains the formation of signal patterning. The next two chapters explain the significance of wavelengths for target detection, probing depths and resolution, and demonstrating the variety of signal presentation. Chapter four discusses why survey results are affected by water and air in the soil, and how this may affect depth readings.
Additional chapters discuss a variety of methods for velocity calibration and suggests where they may be useful, challenging soil conditions and potential problem environments, data processing and a suite of useful techniques, amongst other important topics.
The book gives a clear and formative guidance on understanding the critical factors in using GPR, as well as a checklist of surveying considerations.
- Covers the critical, practical factors in using a ground penetrating radar, including troubleshooting appropriate equipment selection
- Explains why wavelengths matter, providing practice calculations
- Offers insight into how to spot ringing (echo effects) and air signals, and how to distinguish these from subsurface data
- Enables the reader to understand the importance of calibration of transmission velocity and a range of methodsa
Civil, Structural, Geotechnical, and Environmental Engineers, Surveyors, those concerned with brownfield site development, those managing a wide variety of Environmental resources and Archaeologists
1. Introduction to GPR
The “Difficulty” underlying GPR: Visualisation.
How GPR works.
What do the Signals represent?
How Hyperbolas & Lines are formed.
Layers and Large Objects
Implications of the Beam Shape and Survey Direction
The Double Y axis
2. Wavelengths and why they matter
Frequency and Wavelength.
Velocity and Wavelength
Maximum Depth of Penetration
The smallest Target which can be detected
Target spacing – How Close/How far apart?
Fitting the frequency to the application
Practical Examples of Wavelength Calculation
3. More Fundamentals of GPR Operation
What 2d GPR data looks like & why
Wavelength and Signal Amplitude
Signal capture at the ground surface
Signal to Noise ratios.
Data Presentation: Colour and Grayscale
4. The effect of Water and Air
Transmission velocity and misleading depth measurements
The “Rule of 3”
Where Air may be present
Examples of air gaps
Examples of Subsurface Water
The Importance of Velocity Calibration
Practice Calculations of wavelength
5. Velocity Calibration
Calibration by Curve Fitting
Known Layer or Layers
Object at Known Depth
Wide Angle Reflection and Refraction
Transmitter with Multiple Receivers
Other Calibration Rules
Consistency with Site Conditions.
6. Attenuation or Loss
Degrees of Attenuation
Electrical and Magnetic Losses
Near Surface Reflectors
Footnote about Clay, Concrete and Sand
Why a Working Knowledge of GPR Limitations Matters.
7. Survey Strategies
Pre-Set Probing Depths
Sampling along the line of travel of the GPR
Transect Spacing (sampling across the survey area)
Grids & GPS
Information required prior to survey and Decisions to be taken
The Unsuitable Soil Risk
Answers to the Exercise
8. Data Processing
Time zero removal
Other useful techniques (X-flip, cut and paste)
9. Antennas and Screening
Bowties, Horns and Snakes
Size Matters - The Manufacturer’s Rule of thumb.
Common sources of external interference
Detection of air and other above ground signals
10. Three Dimensional Data
Formation of 3-dimensional data
Line Placement Exercise
The Calculations for the Example of the subsurface Empty Cellar
Answer to Line Placement Exercise.
11. Common GPR Applications
Roads and Bridge Deck
Environmental and Glaciology
Detection of Unexploded Ordnance
12. Examples of Practical Problems
Case Study 1: The Potential Gas Explosion Problem (reinforced concrete)
Case Study 2: Detection to a Depth of 5m in reinforced concrete
Case Study 3: Mosaic Construction and Graves inside a Historic Church
Case Study 4: A Wetland Archaeological Site
Case Study 5: Carbonate Concretions in a Salt Marsh
Case Study 6: A Delaminating Floor in a Supermarket
Case Study 7: Detection of UXO in Redeposited Earth
Case Study 8: Bridgedeck Construction
13. Multi-channel and Single channel systems
Single Channel Systems
Duos and Trios
Swept Frequency Systems
14. Reports and Publication
Report title and introduction
Professional Statement of Indemnity
Acknowledgements and References
Third Party Archives
Inappropriate remarks in publication.
European Licensing of Equipment
GPR Operational Requirements: the Code of Practice
GPR Operational Requirements: the Radar Log
European Telecommunications Standards Institute (ETSI)
The European GPR Association (EuroGPR) and its role in licensing matters
North American Equipment Licensing
GPR and Safety of Transmissions
16. Further Reading
Ground Penetrating Radar – General
GPR Utility Detection
Environmental GPR Investigations
GPR Data Processing
Unusual GPR technical claims
GPR Conference Papers
17. Glossary of Common Technical Terms
18. References used in the text
19. Professional Association & Reputable Manufacturers
Finding a Reputable Manufacturer
Unusual Technical Claims
- No. of pages:
- © Butterworth-Heinemann 2017
- 2nd May 2017
- Paperback ISBN:
Erica Carrick Utsi is the former Chairman of the European GPR Association, and the former director of GPR manufacturer – Utsi Electronics Ltd. She is internationally experienced in most applications of GPR, especially in new adaptations and research of the field. She is also the author of a wide range of GPR papers, and was a co-author with David Daniels on GPR case histories and known physical principles.
Former Chairman of the European GPR Association and former director of GPR manufacturer, Utsi Electronics Ltd.