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