A basic introduction to available geophysical test methods for the use of Geotechnical engineers presented at the USACE Infrastructure Conference in Atlanta, June 2011.

1. GEOPHYSICS FOR
GEOTECHNICAL ENGINEERS -
BRIDGING THE GAP
Ramanuja Chari Kannan PE FASCE
CESWF-EC-D
June 15, 2011
Atlanta, GA
US Army Corps of Engineers
BUILDING STRONG®

2. EVOLUTION OF GEOLOGY
The earliest writing on Geology probably
dates back to Theophrastus (372-287BC)
who wrote a book on rocks called ‘Peri
Lithion.”
Abū Rayḥān al-Bīrūnī was perhaps the first
person to document his observations about
the earth and is credited with writing the first
book on Geology. (A crater on the moon and the
University in Tashkent are named after him).
Will Durant in his History of Civilization
recognized that al-Biruni worked on the
hypothesis that the earth was a
sphere, revolved around the sun and
spun on it axis.
The term “geology” was introduced by
Jean-Andrè Deluc in 1778.
William Smith (1769-1839) produced the
first geological map of England and
Ireland.

3. GEOLOGY TODAY
Earth science  Geography Paleoclimatology
Economic geology  Geological modeling Paleontology
Mining geology  Geometallurgy Micropaleontology
Palynology
Petroleum geology  Geomicrobiology Petrology
Engineering geology  Geomorphology Petro physics
Environmental geology  Geomythology Plate tectonics
Geoarchaeology  Geophysics Sedimentology
Geochemistry  Glaciology Seismology
Soil science
Biogeochemistry  Historical geology Pedology (soil study)
Isotope  Hydrogeology Speleology
geochemistry  Meteorology Stratigraphy
Geochronology  Mineralogy Biostratigraphy
Geodetics  Oceanography Chronostratigraphy
Lithostratigraphy
 Marine geology Structural geology
Volcanology

4. GEOTECHNICAL ENGINEERING
The credit for understanding of the concept of
soil as an engineering material should rightfully
belong to Coulomb, who soon after his
graduation in 1761 used his knowledge of
mechanics to apply to pressure exerted by soils.
Karl Terzaghi of course has been credited with not
only coining the term soil mechanics, but also with
realizing the importance of understanding geology in
understanding soil physical properties. As the
saying goes, the rest is history – of soil mechanics.
No one is really sure when and why the term
Geotechnical Engineering came to absorb soil
mechanics, foundation design and anything else
that has the word “soil” in it. Terzaghi’s wife Ruth, a
geologist and his graduate student and Arthur
Casagrande should be credited with connecting
mechanics with the material.

5. MERGING GEOLOGY AND GEOTECHNICAL
ENGINEERING
• Geology and Geotechnical Engineering merge in
many areas – soil and rock physical properties, site
characterization, mineralogy and foundation design.
• While Geotechnical engineers have refined their
laboratory testing, in-situ testing and design
techniques, the amalgamation of geophysics and
geotechnical engineering has not taken a significant
role in the practice of geotechnical engineering.
• Geophysical methods should be the primary
investigative tool for geotechnical engineers.

6. GEOPHYSICAL METHODS
METHOD MEASURED PARAMETER
Ground Penetrating Radar (GPR) Dielectric Constant (indicate the top of rock surface)
Electromagnetic Frequency and Electrical Conductivity (lateral variation in soil and rock;
Time Domain (EFT) differentiate soil types including contaminated soils)
Very Low Frequency (VLF) ER Electrical Resistivity (apparent resistivity)
Electrical Resistivity / Capacitively Electrical Resistivity (stratification/spacial differentiation)
Coupled Resistivity
Spontaneous Potential (SP) Electrochemical and Streaming potential (Seepage)
Seismic Refraction Seismic velocity, shear modulus (rock rippability)
Seismic Reflection Seismic velocity (Stratigraphy)
Surface Wave Analysis Seismic velocity, dispersion (S-wave/stratigarphy, karst
features)
Microgravity Density (bedrock/karst)
Magnetic Potential Magnetic susceptibility (minerals, buried objects)
Thermal Imagery Surface temperature (seepage, karst)
Radio-metrics Natural Gamma Radiation (ores, fracture)
Cross-hole tomography Subsurface profiling, stratigraphy (karst)

7. GEOPHYSICS FOR GEOTECHNICAL ENGINEERS
• Policy Development
• Recruitment and Training
• Data management and analysis
• Risk Assessment and Mitigation
• Consultation and Technical Reviews
• Quality Assurance
• Periodic Inspection and Periodic Assessment
Support

8. RMC’s PROGRAM
• Develop 1-, 5-, 10-, and 30-year infrastructure
investment plans
• Prioritize Issue Evaluations, Dam Safety
Modification Reports, and Construction
• Monitor progress and project management for
dam safety projects
• Support Senior Oversight Group and HQ
efforts to manage funds and queues

9. HOW WE CAN SUPPLEMENT RMC
RMC’s CURRENT CONCERNS OUR RESPONSE AND POTENTIAL
Dam Safety Regulation and Procedures SWF has involved RMC in our DSMS RMC’s
need to define RMC Role role is evolving as we progress
Geotechnical Issues dominate the SWF has one of the strongest staff support
Portfolio and expertise in this area
Risk Based Evaluation is needed SWF has the need to focus in this direction
Organizational Improvement needed We have expertise gathered from CoS,
Border Protection, Force Protection, LEED
and Design experience
Experienced Staff is Scarce We have surplus capacity from time to
time and have a recruiting advantage
Extensive outsourcing to A/E firms SWF has the potential to reduce A/E
outsourcing
Prioritizing and Implementation SWF is lower in priority as compared to NE
and NW

10. A PLAN FOR SWF’s RMC PROGRAM
Within the first 30 days:
Establish and staff the center
Define roles and develop Position Descriptions
Develop a 1-year and 5-year budget
Establish program priorities
Within the first 90 days:
Internal Recruitment and assign responsibilities for the internal
team
Prioritize projects and develop schedules (primarily DSMS and LRP
projects)
Match national resources and develop talent pool
Detailed budgets for DSMS and LRP and funding support

11. SWF’s RMC PROGRAM PLAN
Within the first 1 year:
Get project teams working on specific DSMS and LRP projects
Assist the Levee CoP in developing LSMS methods
Develop detailed 5-year design plan for DSMS and LSMS
Develop Remedial action plans and construction plans
Write contracts for remedial works – standardize if possible
Within the first 5 years:
Set up Inspection Plans based on risk evaluation
Assist Dam and Levee CoPs to develop practice standards
Document strategies from lessons learned
Identify10-year and 60-year needs and needed infrastructure
improvements.

12. THANK YOU