1. Environmental Geomechanics: A Recent Development in Geotechnical Engineering DR. D. N. SINGH PROFESSOR Geotechnical Engineering Division Department of Civil Engineering I.I.T. BOMBAY

2. "...to design and construct public works..."
Civil Engineering
"...to design and construct public works..."
Transformation
Practice of improving and maintaining the built and natural environment to enhance the quality of life for present and the generations to follow

3. Role of Civil Engineers “Designers and Builders of
The Quality of Life…….”
Creators of the Civilised Society Environment
Providing solutions to the needs of a developing global
population
Performers (on a world stage) as strategic thinkers and global managers
Pillars of local Economies
Creating and maintaining complex infrastructure in wealth creation

4. Geotechnical Engineering
Subject Organization
Rock Mechanics
Foundations
Retaining Structures
Seepage/Slopes/Dams
Soil Mechanics
Geomechanics
Environment
Geotechnical Engineering
Challenge
Effect is more
pronounced

5. Environmental Geomechanics
Genesis
Population Explosion
Industrialization
Sluggish and “Don’t bother approach”
Ignorance
Human Greed
Is a Philosophy put in practice to deal with
under-ground “environment” & Problems associated with it
Combination/Blend of
Geotechnical Engg. and Environmental Engg.

6. Waste Disposal Strategies
Above ground storage
No protection Protected by
geologic materials

7. Shallow trench burial
Engineered Backfill geological materials.

8. Deep Disposal
with backfill Protected by
high-retardation geologic material

9. Ascertaining the quality of air, water, and land resources;
Issues are
Ascertaining the quality of air, water, and land resources;
Transport, use, and disposal of hazardous wastes
water and wastewater treatment, and reuse.
Analysis and design of foundation systems, seepage control, earth dams and water resource structures, response of foundations and embankments to
the ENVIRONMENTAL ACTIVITIES
Man made
Natural
industrialization/population explosion
earthquakes/(& to some extent other natural calamities).

10. SCOPE of Environmental Geomechanics
Assessment of pollutants being discharged on/in the soil deposits (Disposal/Handling/storage)
Process by which the pollutants travel in geo-environment
(Contaminant Transport)
Protection of ground water aquifers from contamination
(Containment)
Methods of cleaning the contaminated sites
(Remediation)
Methods of creating “Value added” products
(Recycling & Reuse)

11. Specific Studies on Hazardous wastes
Physical, Chemical, Mineralogical, Electrical and Thermal characterization
Geoenvironmental hazards:
Natural and man made
Recycle and Reuse of Industrial waste(s)
Role of Geotechnical engineering in environmental protection
Surface and subsurface contamination
Characterization of contaminated ground
Geoenvironmental site investigation
Site assessment technologies

12. Soil-Water-Environment Interaction
The Natural Environment
Man Made Environment
Geomicrobiosphere
The Particle Energy Field Theory
Environmental Geotechnical Problems
Requires knowledge from other Disciplines
Bacteriology Biology Chemical Engg.
Climatology Geohydrology Geophysics
Geochemistry Hydrogeology Mechanics
Microgeology Physico-Chemistry Soil Science
Soil Engineering Toxicology
Understanding of Soil response to Environments
(Short & long-term)

13. The Natural Environment
Atmosphere
Biosphere
Oxygen Cycle
Nitrogen Cycle
Carbon Cycle
Hydrosphere
Lithosphere
Geomicrobiosphere Ecosphere
The Cycle of Nature

14. Solid Liquid Man-made Environment Agricultural wastes
Human and Animal wastes
Industrial wastes
Mine wastes……Acid mine waste
(due to oxidation of Iron Sulphide (FeS2) or Pyrites to H2SO4)
Nuclear wastes
Construction Effects (Blasting/Dewatering/debris…)

15. Soil Response to Environments
Soil structures (on/in/with)
Pore fluid characteristics
Soil-heat
Soil-Chemical
Soil Bacteria
Soil-Root
Soil-Electrical
Soil-Liquid (water)

16. Basic concepts of Analysis
Most geotechnical projects occur in nature
Long-term phenomenon
Soil is more sensitive and susceptible to environment
than any other construction material
Loading may greatly affect soil properties but not the only
Parameter to be considered
Think of other factors:
Heat
Moisture (wet/Dry)
Pollution intrusion

17. Classical Soil Mechanics: Some flaws
Specific gravity and Atterberg limits are constant
Void ratio and porosity as indicators of soil deformation
Water in the soil mass is mainly gravity water
(need to consider Environmental water)
Flow through a soil mass is only due to hydrostatic potential
(need to consider thermal/electrical/magnetic/chemical effects)
Constitutive models are arbitrarily chosen.
Stress-strain relationship

18. Soil Classification: Controlling Parameters
Grain-size distribution
Soil Consistency (moisture content) LL PL PI
Present scenario
(Parameters)
% Passing #200 Sieve
Specific surface
pH in pore fluid
Ion-exchange capacity
Absorption & adsorption
Thermal properties (Conductivity, diffusivity, specific heat)
Dielectric constant (Electrical properties)
Proposed scenario
(Parameters)

19. Environmental Geomechanics Laboratory @ IIT Bombay
You are most welcome to Visit the laboratory

20. Thanks for your attention!