Evaluation of Field Operational Characteristics of the Portable Strainmeter System.
Final rept. 15 Dec 68-15 Jun 70,
TELEDYNE GEOTECH GARLAND TX
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The report covers an evaluation of the field operational characteristics of six portable strainmeter systems installed in near-surface tunnels and trenches on and near the Nevada Test Site to make measurements of induced strains from high yield underground explosions. Included is an evaluation of instrument operating characteristics limitations imposed by environmental factors and data processing techniques. It is found that the solid earth tides and atmospheric pressure effect can be subtracted from the data but that additional analysis is necessary to define the temperature effect to determine the usefulness of shallow installations for evaluating the decay characterstics of strain steps. At trench sites, strain appears to strongly influenced by temperature changes below ground surface level but above the floor of the trench. At tunnel sites a significant correlation exists between strain and vault temperature. However, strain changes often occur that bear no meaningful relationship to solid earth tides, atmospheric pressure, or temperature. Author
- Test Facilities, Equipment and Methods