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  • 1
    UID:
    kobvindex_GFZ20190730104545
    Format: iii, 54 Seiten , Illustrationen
    Series Statement: CRREL Report 89-19
    Content: Recent efforts to improve airborne electromagnetic induction- measurement technology and to downsize the related helicopter-towed antenna assembly from about 7.5 m long to about 3.5 m long for use in airborne measurement of sea ice thickness are discussed, as are the results from arctic field testing. Also outlined are the system noise and drift problems encountered during arctic field evaluation, problems that adversely affected the quality of the sounding data. The sea ice sounding results indicate that it should be possible to determine thickness to within 5% for ice floes with moderate relief but that, because of sounding footprint size and current model algorithm constraints, steepsided pressure ridge keels cannot be well defined. The findings also indicate that routine sea ice thickness profiling from an airborne platform is close at hand with further system improvement, as is the apparent capability to determine the conductivity of the sea ice, from which an assessment of sea ice strength can be made.
    Note: CONTENTS Abstract Preface Introduction Pre-field-deployment activities Software development System optimization Improvements of the calibration procedure Real-time processing Small bird design and implementation Other improvements Field activities Snow, ice and seawater data AEM surveys Calibration AEM data processing Post-survey results Processing problem Ground truth data Floe freeboard vs thickness analysis AEM sounding results Concluding remarks Literature cited Appendix A: Blowup of Figure 28
    In: CRREL Report, 89-19
    Language: English
    Keywords: Forschungsbericht
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  • 2
    UID:
    kobvindex_GFZ20200923134647
    Format: vi, 62 Seiten , Illustrationen
    Series Statement: CRREL Report 80-26
    Content: A vital concern to the survivability of hardened underground structures in rock is the relative displacement induced along geologic discontinuities by nearby explosions. Such displacement, commonly termed block motion, can occur along faults, joints, bedding planes and other structural weaknesses in rock. This report documents all occurrences of block motion observed during the development of DIHEST, a series of shallow-buried high explosive experiments designed to simulate the direct induced ground motions from a nuclear surface burst. Instances of block motion are described, along with pertinent details of the explosive arrays, geology and ground motion fields. The influence of these and other factors on the direction and magnitude of block motion is discussed.
    Note: CONTENTS Abstract Preface Conversion factors Introduction STARMET Test description Test results PLANEWAVE II Test description Test results DATEX II Test description Test results HANDEC II Test description Test results ROCKTEST II Test description Test results Summary and discussion Literature cited
    In: CRREL Report, 80-26
    Language: English
    Keywords: Forschungsbericht
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  • 3
    UID:
    kobvindex_GFZ20190918153434
    Format: vi, 91 Seiten , Illustrationen
    Series Statement: CRREL Report 76-28
    Content: Fourier transforms of selected ground-motion time histories from five underground high-explosive and nuclear detonations are used to define the transmission properties (Transfer functions) of three rock types. Absorption, a measure of a rock's energy dissipating characteristics, is expressed for each of the tests as a function of the frequency of transmission. Dispersion results from a variation in transmission velocity with frequency and is described for each test by a phase velocity spectrum. The transmission properties from one of the sites are used to predict a ground-motion time history at that site from another nuclear event. The potential use of Fourier techniques to make ground-motion predictions and to measure in-situ material properties is discussed.
    Note: Contents Section I: Introduction Section II: Analytical procedures 1. Fourier transforms 2. Basic transform properties 3. Transform techniques 4. The transfer function Section II: Parameter studies and program evaluations 1. Analytical parameter study 2. I-TRAIN evaluation 3. S-TRAIN evaluation Section IV: Data 1. DATEX I 2. DATEX II 3. STARMET 4. MINERAL LODE 5. HARD HAT and PILEDRIVER Section V: Analysis of transformed data 1. Absorption 2. Dispersion 3. Transfer function Section VI: Fourier synthesis Section VII: Discussion Literature cited Appendix A: The Fourier integral and series Appendix B: Subroutine FOURT used in analysis Appendix C: I-TRAIN and S-TRAIN programs
    In: CRREL Report, 76-28
    Language: English
    Keywords: Forschungsbericht
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  • 4
    UID:
    kobvindex_GFZ20210210154950
    Format: iv, 23 Seiten , Illustrationen
    Series Statement: CRREL Report 81-11
    Content: Abstract: Relative displacement data from high explosive, shallow-buried bursts in rock are combined with relative displacement data from the contained nuclear explosion MIGHTY EPIC. Analysis of these data yields a preliminary, semi-empirical technique for predicting the location, direction and magnitude of relative displacements in rock from contained explosions. This technique is used to make relative displacement predictions for the DIABLO HAWK nuclear blast.
    Note: CONTENTS Abstract Preface Introduction DIHEST analysis MIGHTY EPIC analysis Geological setting and relative displacement documentation Shear stress analysis 8 Displacement analysis DIABLO HAWK predictions Literature cited
    In: CRREL Report, 81-11
    Language: English
    Keywords: Forschungsbericht
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  • 5
    UID:
    kobvindex_GFZ105553
    Format: iv, 49 Seiten , Illustrationen
    Series Statement: CRREL Report 79-7
    Content: Sediments beneath the Beaufort Sea near Prudhoe Bay, Alaska, were probed at 27 sites using a static cone penetrometer to determine engineering properties and distribution of material types, including ice-bonded sediments. The probe provided both point and casing resistance data and thermal profiles. At five sites these data were correlated with information from adjacent drilled and sampled holes. These control data and the quality of the probe information permitted profiles of sediment type and occurrence of ice-bonded material to be developed along three lines that included various geological features and depositional environments. Material properties were quite variable in the upper 14 m of sediments probed. In general, softer, finer-grained sediments occurred in the upper layers, while penetration refusal was met in stiff gravels to 10 to 12 m below the seabed. Seabed temperatures during the study were all below 0 C. However, because of uncertainties in freezing point values caused by brines, evaluation of the penetration resistance data was required to identify the occurrence of ice-bonded sediments. The coupling of thermal and penetration resistance data revealed that seasonally ice-bonded sediments occurred where the sea ice froze back to or near the seabed. Deeper, perennially frozen sediments also appeared to be present at several probe sites. The penetration data obtained can be used to aid in the design of shallow and deep foundations in both ice-bonded and unfrozen subsea sediments.
    Note: MAB0014.001: ZSP-201-79/7 , CONTENTS Abstract Preface Introduction Equipment Data collection and reduction Data analysis and interpretation Point penetration resistance and material properties Lithologic and temperature profiles Casing penetration resistance Applications Shallow foundations Deep foundations Foundations in permafrost Correlations with laboratory tests Conclusions Selected bibliography Appendix A: Description of penetrometer and test procedures Appendix B: Point resistance and skin friction data
    In: CRREL Report, 79-7
    Language: English
    Keywords: Forschungsbericht
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