Abstract
The present work shows correlations between geophysical and geomechanical properties of phyllite, calc-silicate and lime marble samples from the Styrian Erzberg. It concerns little to predominantly strongly slated phyllites and calc-silicate schists as well as more compact limestone marble, all of which are metamorphically overprinted and show low porosity. Strength and deformation parameters for the respective lithologies were derived from the geophysical measurements and the influence of schistosity and anisotropy were investigated. For this purpose uniaxial compression tests in combination with ultrasonic measurements were carried out perpendicular and parallel to the schistosity surfaces of the respective rock types. The test specimens were loaded at different stress levels until UCS was reached. At each level the velocities of compression and shear waves were measured. Each test started with two loading and unloading loops to determine the static modulus of elasticity. Finally, static and dynamic parameters could be determined and compared from the results. In general, it can be stated that the speeds of elastic waves, especially in brittle rock, are strongly pressure-dependent. It could be observed that with increasing pressure, the speeds of elastic waves also increase, in a more or less exponential way. The greatest influence is exerted by the composition, structure, microstructure and genetic predisposition of the rock and the resulting stress-dependent opening and closing of (micro-) cracks. Under the influence of stress or relaxation, crack formation or compaction processes occur, whereby the direction of pressure on the slate surfaces also plays a major role. The anisotropy effect is often disregarded, but usually causes large fluctuations in the measurement results, which is also shown in the following work. Due to the large number of influencing factors it is not possible to conclude strength and deformation parameters from geophysical measurements alone. However, geophysical investigations can be used to estimate the geomechanical behavior of rocks. Such laboratory measurements are also important to determine rock properties and general relationships between properties.
Translated title of the contribution | Correlations of geomechanical and geophysical parameters on rock samples from the Styrian Erzberg |
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Original language | German |
Qualification | Dipl.-Ing. |
Awarding Institution |
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Publication status | Published - 2020 |
Bibliographical note
embargoed until nullKeywords
- elastic wave velocities
- ultrasonic UCS
- anisotropy
- compression wave
- dynamic modulus of elasticity
- static modulus of elasticity
- Erzberg
- ZaB