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Session 03

Geotechnical Instrumentation Data Analysis Tips and Tricks
(Part 1 • Data Management)

Image of data graph.
Posted November 18, 2021

Geotechnical instrumentation data analysis starts with good planning.

Define the geotechnical questions that need to be answered:

  • Every instrument on a project should be selected and placed to assist in answering a specific question: If there is no question, there should be no instrumentation—Ralph Peck

Define the purpose of the instrumentation:

  • Instrumentation should not be used unless there is a valid reason that can be defended—John Dunnicliff

To set up an instrumentation and monitoring program for success, start with defining the data management requirements for the project

Data Management

  • Identify the parties involved and the needs of each party
  • Define what success looks like before the project starts
  • Select a data management system that is appropriate for your organization/project
  • Conduct system validation testing (small scale pilot program)
  • Management of factory calibration “sheets”
    • procedure for updating calibrations
  • Procedure for data screening
  • Procedure for setting appropriate collection frequencies | reviewing schedules
  • Data calculation instructions (with example)
  • Procedure for plotting data (with example)
  • Procedure for reporting data to Engineer of Record, owner, or stakeholder
  • Automated systems shall include backups | data access | data security

Once the data management requirements are set, determine how data will be collected from each instrument on the project.

Data Collection

  • Collection of instrumentation data
    • Follow manufacturer’s recommendations
    • Documented procedure for data collection
    • Maintain field data records
  • Personnel qualifications and responsibilities
    • Training | Refresher Courses
  • The role of automated data acquisition systems
    • No automatic system can replace engineering judgement
    • Role is to reduce non-value-added work
    • Formal initial readings (on site zero reading at thermal equilibrium)
    • Field calibration for nontraditional sensors
    • High frequency readings until sensor/conditions are stable
    • Lower frequency readings for monitoring
  • Take readings at the rate at which site conditions are changing
    • Consider construction activity
    • Consider requirements of data transmission, processing, and interpretation
    • Collection of unnecessary data should be avoided
      • allowing attention to be focused on the critical parameters to be monitored which can provide early indication of a developing problem
    • Subsets of instruments can be assigned for real-time monitoring
      • to track the vital signs of the structure as a primary detection network and less frequent readings for designated secondary instruments

Now that the raw data is collected and managed in a systematic way, set the procedure for converted the raw data into engineering units that can be used to make quick, informed decision.

Data Processing

  • Provide rapid assessment to detect changes requiring action
  • Summarize and present data to:
    • show trends
    • compare observed with predicted behavior
  • Should be automated wherever possible
    • Raw data should always be retained
    • Automated data conversions should be validated by a qualified person
  • Personnel qualifications
    • requires significant judgement
    • do not delegate to inexperienced personnel

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