This dataset provides mechanical test data for quartz sand (“MAM1ST-300”, Sibelco, Mol, Belgium), gypsum powder (plaster; “Goldband”, Knauf), kaolin clay powder, garnet sand, and mixtures of quartz sand and gypsum powder, used at the Analogue Laboratory of the Department of Geography at the Vrije Universiteit Brussel, Brussels, Belgium, for simulating brittle rocks in the upper crust (Poppe et al., 2019). The measured properties are density ρ, tensile strength T0, shear strength σ, obtained by density measurements, ring-shear tests (RST; at Helmholtz Centre Potsdam GFZ, Germany), direct shear tests, traction tests (at University of Maine, Le Mans, France) and extension tests. The obtained tensile strengths and shear strengths reconstruct two-dimensional failure envelopes for each material. By fitting linear Coulomb and non-linear combined Griffith failure criteria to the characterised failure envelopes (Jaeger et al., 2007), the internal friction coefficient µC, Coulomb cohesion CC and Griffith cohesion CG are obtained. The influence of the material emplacement technique has been investigated in Poppe et al. (2021) to which this data set is supplementary, by repeat characterisation of the above physical parameters under three emplacement conditions, i.e. sieving, pouring (non-dried state) and compaction after pouring (oven-dried state).
We find that densities of the materials and mixtures range from ~1600 kg.m³ (sieved) and ~1700 kg.m³ (compacted) for pure quartz sand to ~600 kg.m³ (poured) to ~900 kg.m³ (compacted) for pure plaster. Tensile strengths range from ~166 Pa (sand) to ~425 Pa (plaster). Velocity ring-shear tests on a 90 wt% quartz sand – 10 wt% plaster mixture show a minor shear rate-weakening of <2% per ten-fold increase in shear velocity. The materials show a behavior ranging from Mohr-Coulomb behavior for the materials with coarser grain size (sands) to combined Griffith-Mohr-Coulomb behavior for the powder materials (plaster, kaolin), with the sand-plaster mixtures occupying a spectrum between both end-members. Peak friction coefficients range from ~0.5 (sand) to ~0.6 (plaster) with a maximum of ~0.9 (80:20 wt% sand:plaster), peak Coulomb cohesions range from 13 Pa (sand) to 248 Pa (plaster), peak Griffith cohesions range from ~10 Pa (sand) to ~425 Pa (plaster).
An experimental investigation was implemented to explore the mechanical parameters of the Odenwald reservoir granitoids. The specimen within this research project was the Odenwald Granodiorite (ODG) which was extracted from the quarry on Bergstrasse in Heppenheim, Germany. The study enfolds fundamental mechanical features from intact cylindrical rock specimens.
The ODG was extracted from an active quarry and the extracted blocks were drilled into cylindrical samples. Thereafter, the samples were operated on the Mechanical Testing System (MTS) from the GFZ in Potsdam. This offers the possibility to test the rock strength, including tensile and compressive strength values, of different kind of rock materials.
Fundamental mechanical analysis including Brazilian Disk Test (BD), Uniaxial Compressive Strength Test (UCS) and Triaxial Compression Strength Test (Triax) were part of this experimental investigation. Firstly, the BD was executed to achieve the tensile strength (T0) at different loading rates (0.001 mm/s and 0.0003 mm/s) as well as the fracture toughness mode I (KIC) after Guo from 1993. These samples have a size of 50 mm in diameter and 25 mm in length. Secondly, the UCS resulted in the Poisson’s ratio (ѵ), the static Young’s modulus (E) and the maximum uniaxial compressive strength (Co). Thirdly, the Triax was done under saturated and dry conditions. Hereby, the maximum compressive strength (σ1), the compressibility (C) and the Biot coefficient were calculated from raw data. The Triax experiments have four different setups. Three different confining pressure were executed at different specimens, 20 MPa, 40 MPa and 60 MPa. Additionally, a multiple failure test was executed including all three confining pressure steps. Both experimental setups, UCS and Triax, have samples of the size of 50 mm in diameter and 100 mm in length. All these samples were dried at 60°C for at least 24h and only some Triax experiments were done under saturated conditions.
The data publication includes the raw data files from the experiment as well as files with calculated results for the above mentioned different mechanical parameters. These files are either given as DAT files or Microsoft Excel sheets summarized in a Zip folder. For further details, the full description of the data and methods is provided in the data description file. The samples used in this data publication are assigned with International Generic Sample Numbers (IGSN). These IGSN numbers can be resolved with https://igsn.org/[igsn_number] and link to the sample description in the internet.