Enhanced study of rock elastic anisotropy

0473296 - GLÚ 2017 RIV US eng C - Conference Paper (international conference)
Lokajíček, Tomáš - Svitek, Tomáš - Wenk, H.-R.
Enhanced study of rock elastic anisotropy.
50th US Rock Mechanics / Geomechanics Symposium 2016. Vol. 3. Houston: American Rock Mechanics Association (ARMA), 2016, s. 2492-2500. ISBN 978-151082802-5.
[US Rock Mechanics / Geomechanics Symposium /50./. Houston (US), 26.06.2016-29.06.2016]
R&D Projects: GA MŠMT LH13102
Institutional support: RVO:67985831
Keywords : microstructure * neutron diffraction * rock mechanics * rocks * seismic waves * shear waves * spheres * ultrasonic applications * velocity * velocity measurement
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)

We present a combined study of a classical rock sample from Val Malenco, Italy, by investigating the microstructure and texture with state-of-the art synchrotron X-ray, neutron diffraction methods and measuring ultrasonic velocities both with a multi anvil apparatus and a novel instrument to measure P and S velocities on spheres. Petrological properties were studied by thin section analysis. Both, synchrotron and neutron diffraction data were analyzed for preferred orientation with the Rietveld method. The program MAUD was used for texture analysis. Velocity measurements were done by classical measurements of P- and S-wave velocities using the pulse transmission technique at room temperature and pressures up to 600 MPa with a triaxial apparatus. There was also measured 3D velocity distribution of spherical samples by P- and S-wave ultrasonic sounding. Determination of P, S1 (fast) and S2 (slow) wave velocities enables to calculate a full stiffness tensor. The crack distribution from non-linear approximation of P-wave measurements on sphere was determined. From quantitative texture measurements, elastic properties are modelled by self-consistent averaging. Comparison of experimental and model Cii parameters is done based on microstructures. Both, results from diffraction methods and velocity measurements are compared. Good agreement between the velocity and microstructural models is observed.
Permanent Link: http://hdl.handle.net/11104/0270452