Environmental Geomechanics: A Recent Development in Geotechnical Engineering DR. D. N. SINGH PROFESSOR Geotechnical Engineering Division Department of Civil Engineering I.I.T. BOMBAY [e-mail]

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Environmental Geomechanics A Recent Development
in Geotechnical Engineering DR. D. N.
SINGHPROFESSORGeotechnical Engineering
DivisionDepartment of Civil EngineeringI.I.T.
BOMBAYdns_at_civil.iitb.ac.in
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Civil Engineering
Transformation
Practice of improving and maintaining the built
and natural environment to enhance the quality of
life for present and the generations to follow
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• 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

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Subject Organization
Effect is more pronounced
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Environmental Geomechanics

• Genesis
• Population Explosion
• Industrialization
• Sluggish and Dont 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.

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Waste Disposal Strategies Above ground
storage No protection
Protected by
geologic materials
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Shallow trench burial Engineered
Backfill geological materials.
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Deep Disposal with backfill
Protected by high-retardation
geologic material
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• 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).
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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)
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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

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Soil-Water-Environment Interaction
The Natural Environment
Man Made Environment
Geomicrobiosphere
The Particle Energy Field Theory
Environmental Geotechnical Problems
Requires knowledge from other Disciplines Bacterio
logy 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)
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The Natural Environment

• Atmosphere
• Biosphere
• Oxygen Cycle
• Nitrogen Cycle
• Carbon Cycle
• Hydrosphere
• Lithosphere
• Geomicrobiosphere Ecosphere

The Cycle of Nature
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Man-made Environment
Solid Liquid

• Agricultural wastes
• Human and Animal wastes
• Industrial wastes
• Mine wastesAcid mine waste
• (due to oxidation of Iron Sulphide (FeS2) or
  Pyrites to H2SO4)
• Nuclear wastes
• Construction Effects (Blasting/Dewatering/debris)

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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)

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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
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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
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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)
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Environmental Geomechanics Laboratory _at_ IIT Bombay

• www.civil.iitb.ac.in/dns

You are most welcome to Visit the laboratory
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Thanks for your attention!