Deformation monitoring

Deformation monitoring

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Deformation monitoring is the systematic measurement and tracking of the alteration in the shape or dimensions of an object as a result of stresses induced by applied loads. Deformation monitoring is a major component of logging measured values that may be used to for further computation, deformation analysis, predictive maintenance
Predictive maintenance
Predictive maintenance techniques help determine the condition of in-service equipment in order to predict when maintenance should be performed...

 and alarming.

Deformation monitoring is primarily related to the field of applied surveying, but may be also related to the civil engineering, mechanical engineering, plant construction, soil and rock sta-bility mechanics.

The causes for deformation monitoring are changes in the bedrock, increase or decrease of weight, changes of the material properties or outside influences.

The used measuring devices (1) for a deformation monitoring depend on the application (2), the chosen method (3) and the required regularity (4).

Measuring devices


Measuring devices (or sensors) can be sorted in two main groups, geodetic and geotechnical sensors. Both measuring devices can be seamlessly combined in modern deformation monitoring.
  • Geodetic measuring devices measure georeferenced displacements or movements in one, two or three dimensions. It includes the use of instruments such as total station
    Total station
    A total station is an electronic/optical instrument used in modern surveying. The total station is an electronic theodolite integrated with an electronic distance meter to read slope distances from the instrument to a particular point....

    s, levels
    Dumpy level
    A dumpy level, builder's auto level, leveling instrument, or automatic level is an optical instrument used to establish or check points in the same horizontal plane...

     and global navigation satellite system receivers.

  • Geotechnical measuring devices measure non-georeferenced displacements or movements and related environmental effects or conditions. It includes the use of instruments such as extensometers, piezometer
    Piezometer
    A piezometer is either a device used to measure static liquid pressure in a system by measuring the height to which a column of the liquid rises against gravity, or a device which measures the pressure of groundwater at a specific point...

    s, rain gauge
    Rain gauge
    A rain gauge is a type of instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a set period of time....

    s, thermometer
    Thermometer
    Developed during the 16th and 17th centuries, a thermometer is a device that measures temperature or temperature gradient using a variety of different principles. A thermometer has two important elements: the temperature sensor Developed during the 16th and 17th centuries, a thermometer (from the...

    s, barometer
    Barometer
    A barometer is a scientific instrument used in meteorology to measure atmospheric pressure. Pressure tendency can forecast short term changes in the weather...

    s, tilt meters
    Inclinometer
    An inclinometer or clinometer is an instrument for measuring angles of slope , elevation or depression of an object with respect to gravity...

    , accelerometer
    Accelerometer
    An accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration , but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame...

    s, seismometer
    Seismometer
    Seismometers are instruments that measure motions of the ground, including those of seismic waves generated by earthquakes, volcanic eruptions, and other seismic sources...

    s etc. Or refer to geotechnical sensors
    Sensor
    A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...

     for more detail.

  • Other techniques e.g. radar measuring devices
    Slope stability radar
    The Slope Stability Radar is a new application for the monitoring of slope stability at open-cut mines. It is a system currently in use across the global mining and civil industries....

    .

Application


Deformation monitoring can be required for the following applications:
  • Dam
    Dam
    A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

    s
  • Roads
  • Tunnels
  • Bridges and Viaducts
  • High-rise and historical buildings
  • Foundations
  • Construction sites
  • Mining
  • Landslide and Volcanoes
    Volcanology
    Volcanology is the study of volcanoes, lava, magma, and related geological, geophysical and geochemical phenomena. The term volcanology is derived from the Latin word vulcan. Vulcan was the ancient Roman god of fire....

     Slopes
  • Settlement areas
  • Earthquake areas

Methods


Deformation monitoring can be made manually or automatically.
  • Manual deformation monitoring is the operation of sensors or instruments by hand for the purpose of deformation monitoring.

  • An automatic deformation monitoring
    Automatic Deformation Monitoring System
    An automatic deformation monitoring system is a group of interacting, interrelated, or interdependent software and hardware elements forming a complex whole for deformation monitoring that, once set up, does not require human input to function. Automatic deformation monitoring systems provide a...

    system is a group of interacting, interrelated, or interdependent software and hardware elements forming a complex whole for deformation monitoring that, once set up, does not require human input to function.


Note that deformation analysis and interpretation of the data collected by the monitoring system is not included in this definition. An automatic monitoring system may be used for periodic or continuous monitoring.

Regularity and scheduling


The monitoring regularity and time interval of the measurements must be considered depending on the application and object to be monitored. Objects can undergo both rapid, high frequency movement and slow, gradual movement. For example, a bridge might oscillates with a period of a few seconds due to the influence of traffic and wind and also be shifting gradually due to tectonic changes.
  • Regularity: ranges from a days, weeks or years for manual monitoring and continuous for automatic monitoring systems.

  • Measurement interval: ranges from fractions of a second to hours.

Risk management


Deformation monitoring systems provide a proactive control of a hazard related to possible change or failure of a structure. Policyholders can reduce risk exposure before and during construction and throughout the lifecycle of the structure and hence decrease the insurance premium.
Refer to Risk Management
Risk management
Risk management is the identification, assessment, and prioritization of risks followed by coordinated and economical application of resources to minimize, monitor, and control the probability and/or impact of unfortunate events or to maximize the realization of opportunities...

 for more detail.

See also

  • Automatic deformation monitoring system
    Automatic Deformation Monitoring System
    An automatic deformation monitoring system is a group of interacting, interrelated, or interdependent software and hardware elements forming a complex whole for deformation monitoring that, once set up, does not require human input to function. Automatic deformation monitoring systems provide a...

  • Deformation Survey
    Surveying
    See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...

  • Engineering Geology
  • SAA - ShapeAccelArray
  • Slope stability
    Slope stability
    The field of slope stability encompasses the analysis of static and dynamic stability of slopes of earth and rock-fill dams, slopes of other types of embankments, excavated slopes, and natural slopes in soil and soft rock...

  • Structural health monitoring
    Structural health monitoring
    The process of implementing a damage detection and characterization strategy for engineering structures is referred to as Structural Health Monitoring . Here damage is defined as changes to the material and/or geometric properties of a structural system, including changes to the boundary conditions...


Further reading


External links