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Method Name: |
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Seismic vibration control |
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Method Type: |
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Seismic Techniques
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Assigned Problems: |
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Principle: |
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Monitoring of seismic emission of civil engineering activities (e.g., construction site activities), blasting and traffic in buildings and other engineering structures. |
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Keywords: |
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Seismic Techniques; Seismic vibration control; Acoustic shocks; Seismic emissions; Engineering structures; Amplitude-frequency analysis |
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Prerequisites: |
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- Accurate surveying of geometry and topography are required.
- Complex subsurface geology may lead to misinterpretation in 2-D profiles.
- Target must be characterized by a seismic impedance contrast.
- In Switzerland the VSS norm 640 312a gives rules and reference values in according to the building category, type of vibrations and the main vibration frequency. Evaluate the source(s) of vibrations (expected duration; frequency; intensity).
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Resolution: |
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NA |
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Expected Results: |
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- Measured parameter: Velocity of ground motion (as determined by the voltage generated by the calibrated geophone recording system).
- Data analysis: Processing of seismic vibration control yields amplitude vs. frequency diagram and enable a focus on the time period of interest. Analysis of maximum amplitudes vs. frequency.
- Interpretation: Seismic interpretation assumes that the resolved reflectors represent true lithological interfaces. Additional geological or geophysical surface data may be required for reliable interpretation. Analysis of maximum amplitudes, number of events / h or day or night
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Combination with other Methods: |
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- Required additional information: Geological information is necessary for the interpretation. Sensitivity may vary within a structure; thus, foregoing measurements at several locations may be necessary. Geological information about the subsurface between the source and target, information about building or engineering structures like foundation, material of walls and ceilings, dimensions, separation of the building in zones and areas depending of their use.
- Related add-on information: Reflection seismic data, Refraction seismic data, Surface-based tomographic data.
- Independent additional information: In some cases displacement measurements on cracks (fissures) of the controlled objects are recommended.
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Operating Expense: |
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- Crew size: Generally 1 - 2 persons (depends on complexity of problem)
- Acquisition speed: Standard measurements for one building take 4 hours. (depends on complexity of the problem)
- Processing: 2 -6 hours for a standard measurement of a building
- Equipment rental costs:low to medium
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Parameters to specify: |
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- Source type / Source parameters (e.g., amount of explosive, hammer, weight-drop, vibrators).
- Instrument type (natural frequency should be 4.5 Hz or lower).
- Frequency range to record (at least between 5 and 150 Hz).
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QC Documents: |
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- Coordinates and map of shot and receiver locations.
- Geodetic survey.
- Calibration data.
- Field notes (e.g., all activities, effective time schedule, present personnel).
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Products: |
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- Raw data and geometry files.
- Recordings (particle velocity in three orthogonal directions) with frequency analysis.
- Interpretation.
- Optional: Test measurements (i.e., ""walk-away"" tests, source tests, geometry test of array).
- Optional: Modelling of the detectability of an anomaly with the employed source-receiver geometry.
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