## 5 Conclusions  
Based on the conducted studies summarized in Section 4, the chosen representation for the investigated strain curves in terms of polar diagrams for specimens with different isotropy plane inclinations proved to be suitable for depicting the influences of different elastic parameters. Confronting such curves, based on calibrated elastic parameters, with the actual strain measurements can also be useful to identify inaccurate measurements and outliers in practice. Non-uniform radial strain distributions are generally obtained for transversely isotropic samples. Only for the case of horizontal planes of isotropy or specific combinations of the elastic constants and ratios between them is strain uniformity reached. From visual inspections of the generated strain distributions, it is evident that the gradients of the strain curves for parameter sets resulting in concave shapes are highest in the vicinity of strain measures along the \(x\)- and \(y\)-axis, as usually considered for the calibration of the elastic constants. This underlines the significance of the precise positioning of strain gauges and/or measurement extensometers to prevent substantial inaccuracies in the calibration results for the elastic constants. From the presented approaches for setting up the numerical models, defining the boundary and loading conditions and carrying out the evaluation of strains, it was demonstrated that the analytical results can be satisfactorily reproduced. A clear effect of interface friction on the resulting axial stress distributions was detected, with the highest influence given for samples with an isotropy plane inclination of \(\beta=45^{\circ}\). The resulting strains at the central cross section showed almost no dependency on the considered interface friction, except for the radial strains of the samples with \(\beta=45^{\circ}\). By evaluating the results of 15 numerical UCS test simulations on moderately anisotropic rock samples, i.e., \(E/E^{\prime}\)\(\sim\)2, with friction considered at the sample-platen contacts and varying values for the transverse shear modulus \(G^{\prime}\) and ratio \(\
u/\
u^{\prime}\), it was found that both variation parameters affect the resulting strains in the \(x\)-direction for samples with inclined planes. High values for \(G^{\prime}\) in combination with low ratios \(\
u/\
u^{\prime}\) resulted in the maximum difference between analytical and numerical values for the strain component \(\epsilon_{x}\) of \(\sim\)15%. Despite this high discrepancy, the value of the back-calibrated transverse shear modulus \(G^{\prime}\) only diverged by \(\sim\)3% from the value as used for the simulation. This range is considered too small to justify the requirement of friction-reducing measures, e.g., ball-bearing plates, within UCS tests on moderately anisotropic rocks. Considering that, in physical UCS tests, plasticity and complex micro-mechanical processes are also contributing to the developing sample strains, specimen end-effects might not be the biggest contributing factor toward inaccuracies in calibration results provided that the strain measurements are carried out locally. The findings of the present research on the elastic behavior of transversely isotropic cylindrical rock specimens under uniaxial compression can be summarized as follows:  
* The majority of transversely isotropic rocks possess elastic parameters that fall within observable standard domains. * A polar representation of analytical strain distributions confronted with actual measurement values can help in identifying bad measurement results. * Slight deviations from the optimum strain measurement directions may result in large errors in the measurements given that strain gradients are highest in close proximity to these directions. * Provided that local strain measurements are carried out, a practically relevant influence of end-effects is only to be expected for generated radial strains around samples with inclined isotropy planes.