AutoAdaptive Media in Geotechnical Earthquake Engineering

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AutoAdaptive Media in Geotechnical Earthquake
Engineering

• Report of the Shoal Creek
• Discussion Group
• Research Applications
• Austin, January 10-12, 2001

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AutoAdaptive Media in Geotechnical Earthquake
EngineeringGENERAL RESEARCH AREAS

• Seismic Ground Hazard Assessment
• Pre-Earthquake Hazard Mitigation
• Realtime EQ Monitoring Seismic Response
• Post-EQ Health Monitoring Detection

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Seismic Ground Hazard AssessmentFocus Areas

• Liquefaction Potential
• Landslides and Slopes
• Microzonation Site-Specific Soil Properties
  Determination
• Site Response Ground Amplification

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Pre-Earthquake Hazard MitigationFocus Areas

• Soil Densification and Improvement
• Foundation Systems Improvement
• Construction QA/QC
• Slope Stabilization

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Realtime Earthquake MonitoringFocus Areas

• Ground Motions (horiz. vert. arrays)
• Porewater Pressures
• Permanent Deformations (GPS Utilities made with
  smart alloys)
• GIS with all data monitors networked

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Post-Earthquake Health MonitoringFocus Areas

• Permanent Deformation Measurements
• Integrity Testing
• Soil and Rock Instability
• Residual Porewater Pressures

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Geotech EQE Problems Needs

• Accurate measurements of low-strains in lateral
  load tests
• Measurements of soil stresses
• Dynamic Strain Measurements
• Soil Sampling of Clean Sands
• Calibrating Sensor In-Situ for Tornado Detection

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Geotech EQ Problems Needs

• Measuring Strains Due to Blasting
• Pressure Transducers to Survive Blasts and still
  Measure Low-Pressures, Integrating Deflection
  Sensors
• Measurements of Pile Lateral Deflections, also
  Gaps
• Position Sensitive Detector (PSD) to Measure
  Displacement Vibration

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Problems Needs

• Array of sensors and receivers to measure
  changes in wave velocity during induced
  liquefaction
• Transducers to excite vibrocone (piezo-actuator)
• Deflection sensors matching ground impedance and
  density
• In-Situ Dynamic Strain Damping Measurements

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Research Solutions Using AAM

• Installation of 3-D array of MEMs and/or Piezo
  Stacks for Tomographic Mapping of Vs during
  Liquefaction
• Blast-Induced Liquefaction at Treasure Island/CA
  and Cooper River Bridge/SC

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Research Solutions Using AAM

• Liquefaction Effects on CPT qc and in-situ Vs
• Time effects on qc and Vs after liquefaction
• Arrays of MEMs and Piezoelectric Stacks (BE)

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Sampling Methods

• Magneto-Rheological Drilling Fluids
• Impregnates clean sands for undisturbed samples
  until confined within triaxial apparatus

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Site Characterization Methods

• Vibrocone Penetrometer for Site-Specific
  Liquefaction Evaluation
• Dynamic Forces imparted by piezostack for
  controlled frequency, displacements, loads.

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Advanced Geotechnical Exploration

• Opto-electro-mechanical sensors with digital
  output for subsurface image collection at
  variable focal lengths.
• Enhancement on the VisCPT concept for
  high-resolution stratigraphic profiling.

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Lifeline/Utility Connections

• Shape-memory alloys

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Advanced Reinforced Earth Structures

• Use principles of active dampers from buildings
  to reinforced earth retention walls
  embankments.
• Piezo-polymer geosynthetics (smart
  geosynthetics)

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AAM Ground Improvement

• During seismic event, Smart System controls pump
  drawdown from wells to reduce excess porewater
  pressures.
• Vacuum consolidation

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Self-Diagnosing Foundation System

• Fiber optics and/or Time Domain Reflectometry
  (TDR).
• Self-Leveling Foundation Systems

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Need Permanent DeformationMeasurement Devices

• GPS
• Measure barometric pressures with AAM ?
• PSD (position sensitive detector)
• SAR (remote sensing)
• TDR

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Permanent Deformations

• Network System of Motes (Glaser)
• Each Mote connected to a vertical or angled fiber
  optics sensor (hybrid AAM)

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Centrifuge Modeling with MR fluid soils

• Where do the sand particles go when liquefaction
  occurs
• Use sand with mixed magneto-rheological
  properties
• Magnetic sensing tools to trace where the sand
  flowed