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

‹ Session 02 • Session 04 ›