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a presentation on the subject matter of geotechnical engineering practices and its relevance to foundation design and other civil engineering disciplines
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QIPQIP--Short Term CourseShort Term CourseGeotechnical Engineering Practices and Developments Geotechnical Engineering Practices and Developments
66thth 1010thth January, 2014, IIT January, 2014, IIT GuwahatiGuwahati
Arindam Arindam DeyDeyAssistant ProfessorAssistant ProfessorDepartment Department of Civil of Civil EngineeringEngineeringGeotechnical Engineering DivisionGeotechnical Engineering DivisionIIT IIT GuwahatiGuwahati
Mother Earth is Ultimate Support
Soil Quotes Another one bites the dust
The phoenix rises from its own ashes Ashes are not really soils, but today we have fly-ash
Geotechnical Engineering First, foremost and basic course
Soil Mechanics and Foundation Engineering
Soil Mechanics Soil formation and characterization Soil phase relationships, index properties and
Foundation Engineering Shallow foundations
Ultimate bearing capacity Soil phase relationships, index properties andclassifications
Soil permeability and seepage Effective stress and pore-water pressure Stress distribution Compressibility and consolidation Shear strength of soils Soil exploration Slope stability Lateral earth pressures
Ultimate bearing capacity Settlement
Isolated footings Combined and Mat footings
Deep foundations Pile foundations Pile Groups
Vertically and laterally loadedpiles
Retaining walls Sheet pile walls and braced excavations
What Engineers are we ???
Mixed-Breed Engineers Geotechnical Engineering
Much more than solely Soil Mechanics and Foundation Engineering
Geotechnical engineers are Shadowcats Have a separate identity
Have a separate identity Can blend as per requirement and necessity
We are MIXED-BREED ENGINEERS
Soil-Structure Interaction (SSI) Blending of structural and geotechnical engineering
Contributory Parameters Static and Dynamic strength and stiffness properties of soils
Footing/Foundation design Identify the structural load transferred from column to soil Estimate the safe bearing capacity of the soil Determine footing dimensions Estimate the settlement and check against permissible value
If the design fails, go for another trial or change the footing type
Foundations on Difficult Subsoils Conventional foundation design fails under difficult subsoil
conditions Local erosion
Underground defects
Foundations on Difficult Subsoils Conventional foundation design fails under difficult subsoil
conditions Unconsolidated filled up soil
Expansive soils
Foundations on Difficult Subsoils Conventional foundation design fails under difficult subsoil
conditions Frost action
Desiccation
Foundations on Difficult Subsoils Sometimes it may be a Disaster,
at time it may be a Marvel
Soil-Foundation-Structure Interaction (SFSI) Minimum spacing of footings
Interference of pressure bulbs
Soil-Foundation-Structure Interaction (SFSI) Static interaction of adjacent structures
Soil-Foundation-Structure Interaction (SFSI) Dynamic/Seismic interaction of adjacent structures (Iguchi et
al., 2009)
Front view of BRI annex building (left) and main building (right). These two
buildings are connected by passage ways Multi-mass model of a soil-structure system
Soil-Foundation-Structure Interaction (SFSI) Aspects of SSI (Liam Finn, 2010)
Schematic drawing of model of 54 storey building with several basement levels
Most accurate model of 54 storey building
Soil-Foundation-Structure Interaction (SFSI) Aspects of SSI (Liam Finn, 2010)
Model with no foundation interaction
Rigid base with passive lateral restraint
Building rigidly fixed to the soil even along the
basement walls
Soil-Foundation-Structure Interaction (SFSI) Aspects of SFSI (Liam Finn, 2010)
Computational model of bridge bent including pile foundation
Computational model of bridge superstructure
Soil-Foundation-Structure Interaction (SFSI) Dynamic soil-foundation-structure interaction model
(Moghaddasi et al., 2010)
Dynamic soil-shallow foundation-structure model for horizontal and rocking
foundation motions
Geo-Hydrology Blending of Geotechnical and Water Resources engineering
Contributory parameters Hydraulic head, porosity, water content, hydraulic conductivity, specific
storage and specific yield, contaminant transport properties,
Confined and Unconfined Aquifers
Confined and Unconfined Aquifers
Geo-Hydrology Blending of Geotechnical and Water Resources engineering
Contributory parameters Hydraulic head, porosity, water content, hydraulic conductivity, specific
storage and specific yield, contaminant transport properties,
Groundwater flow estimation
Groundwater flow estimation
Geo-Transportation: Pavement Geotechnology Blending of Geotechnical and Transportation engineering
Paved and Unpaved roads
Geo-Transportation: Pavement Geotechnology Blending of Geotechnical and Transportation engineering
Geotechnical issues leading to pavement failures Insufficient subgrade stiffness/strength Moisture/Drainage problems
Cycles of freezing and thawing
Cycles of freezing and thawing Swelling soils Contamination problem Erosion Spatial variability of soils
Geo-Transportation: Pavement Geotechnology Pavement distresses from geotechnical issues
Normal rutting
Excessive rutting
Aggregate contamination or degeneration
Geo-Transportation: Pavement Geotechnology Pavement distresses from geotechnical issues
Subgrade pumping
Drainage problems
Frost action
Geo-Transportation: Pavement Geotechnology Pavement distresses from geotechnical issues
Swelling soils
Differential settlement
Collapsing soils, Karstcondition or Liquefaction
Geo-Transportation: Railway Track Geotechnology Ballasted railway track section
Contributory geotechnical properties Strength and stiffness of ballast and subgrade
Geo-Transportation: Railway Track Geotechnology Railway track distresses from geotechnical issues
Ballast degradation Fouled BallastDifferential settlement
Geo-Transportation: Railway Track Geotechnology Railway track distresses from geotechnical issues
Improper drainage Water ponding
Geo-Transportation: Railway Track Geotechnology Railway track distresses from geotechnical issues
Clay pumping Dried slurry
Track buckling due to less lateral confinement
Environmental Geotechnology Blending of Geotechnical and Environmental engineering
Contributory geotechnical parameters Permeability and hydraulic conductivity, Chemical characteristics of soils
Landfill cover and waste containment system
Ground Engineering and Improvement Blending Geotechnical and Mechanical/Hydraulic engineering
Objective of ground improvement Modify and improve the soil characteristics
Increase in density and shear strength to aid problems in stability
Increase in density and shear strength to aid problems in stability Reduction of soil compressibility Influence permeability to reduce or control ground water flow or to increase
the rate of consolidation Improve soil homogeneity
Ground Engineering and Improvement Ground improvement techniques
Preloading with Prefabricated Vertical Drains (PVDs) Preloading arrest post-construction settlement PVD aids in quick dissipation of pore water pressure and accelerated
consolidation
A typical band drain with core and filter sleeve
Ground Engineering and Improvement Ground improvement techniques
Vibrocompaction and Vibro-replacement techniques Vibrocompaction is used in granular soils Vibro-replacement is mostly used in cohesive soils
Vibrocompaction Vibro-replacement
Ground Engineering and Improvement Ground improvement techniques
Grouting and Hydraulic Fracturing Grouting is used to fill up the existing cavities in the subsoil Hydraulic fracturing creates a web of cavities which is subsequently filled up
to enhance subsoil strength
Jet Grouting Hydraulic Fracturing
Ground Engineering and Improvement Ground improvement techniques
Lime/Cement columns and In-situ soil mixing Lime/Cement column used to stabilize soft clay and silt as well as organic
soils In situ soil mixing mainly used for soil stabilization and column-type
reinforcement of soft soils
reinforcement of soft soils
Lime/Cement column In-situ soil mixing
Reinforced Soil Structures Objective of reinforced soil structures
Strengthening the existing soil structures Construction of strengthened soil structures
Various forms of reinforced soil structures
Geosynthetics form a major group of reinforcement elements
Reinforced Soil Structures Various forms of reinforced soil structures
Reinforced retaining wallsReinforced embankments
Reinforced Soil Structures Various forms of reinforced soil structures
Reinforced pavement and railway subgrades
Reinforced foundation beds
Reinforced Soil Structures Various forms of reinforced soil structures
Rock bolting
Fiber reinforcement
Reinforced Soil Structures Various forms of reinforced soil structures
Soil nailing Earth anchors
Forensic Geotechnical Investigation Forensic geotechnical engineering
Involves analysis of a project, site conditions, or construction form ageotechnical standpoint
Domain of forensic geotechnical investigation Expansive and collapsible soils
Settlement of shallow and deep compacted fill soils
Settlement of shallow and deep compacted fill soils Moisture intrusion below slabs Soil corrosion and sulfate exposure Site runoff and drainage Roadway and parking area pavement failures Slope stability, foundation and excavation failures Site quality analysis Underground pipeline failures
Forensic Geotechnical Investigation Forensic investigation of failure of Sadd-el-Kafara: Worlds
oldest dam (Kumar and Dey, ISFGE, 2012) Involved slope stability failure analysis (using GeoStudio v2012) of the
dam under static and impact hydrodynamic forces
0.639
Reliability based Analysis in Geotechnical Engineering Bearing Capacity of Single Pile in Sand: Reliability Analysis
using Monte-Carlo Simulation (Dey and Kudmetha, IGC, 2013) Assess the reliability of the usage of several empirical expression
commonly in pratice to determine corrected N-value and subsequently thebearing capacity of single pile foundation
Advanced Foundation System Analysis Compensated Raft Foundation on a Preloaded Soil Improved
by Vertical Drains (Reddy and Dey, ICGE, 2014) Assess the possibility of using compensated raft resting on preloaded
soil improved by PVDs as an better alternative to the pile foundation forIITG hostels Application of PLAXIS FE modeling
Scour Effect Analysis Lateral Load Capacity of Piles in Stratified Deposits Subjected
to Scour (Yadav and Dey, IGC, 2013) Calibrate the degradation of lateral load capacity of a single pile
embedded in stratified deposit with the scour phenomenon using OASYSALP
Ambient Vibration Monitoring A full scale instrumented embedded retaining wall: First
interpretation of the measurements using numerical tools (Deyet al., ICEGE, 2011; Rainieri et al., IGC, 2013)
Estimate the vibration signatures of an embedded retaining sheet pilewall using in-situ instrumentations and long-term monitoring andanalysis of recorded acceleration signatures by modeling in PLAXIS 2D
analysis of recorded acceleration signatures by modeling in PLAXIS 2D
Dam-Reservoir-Foundation Hydrodynamic Interaction Seismic Response of Concrete Gravity Dams considering
Hydrodynamic Effects (Dey and Sawant, ISCM, 2013) Assess the hydrodynamic effect on the seismic response of concrete
gravity dam through numerical modeling using GeoStudio
Advanced Retaining System Analysis Rotational stability of rigid cantilever sheet pile walls (Kumar
and Dey, NESG, 2013) Assess the rotational stability of rigid cantilever sheet pile wall
considering partial mobilization of passive pressure
Unpaved Road Geotechnology Quasi-Static Analysis of Geotextile Reinforced Unpaved Roads
Resting on c- Subgrade (Meena et al., PSBS, Elsevier, 2013) Assess the thickness of the aggregate cover required fro an unpaved
road reinforced using a geotextile at the aggregate-subgrade interface
MASW and Subsurface Characterization Subsurface Characterization using MASW: Preliminary
Experimentation and analysis (Taipodia and Dey, NCRACE,2013)
Assess the applicability of NDT method through MASW to identify thesubsurface shear wave velocity profile through signal processing andinversion phenomenon
inversion phenomenon
Summary Geotechnical engineering is much more than simply Soil
Mechanics and Foundation Engineering
Several novel and inter-disciplinary avenues exist whichrequire the aid and blend of geotechnical engineers
require the aid and blend of geotechnical engineers
Geotechnical Engineering is a Science,But its Practice is an Art
Karl Terzaghi
Thank You for Patient Hearing