Fig. 5

Comparison of different parameters for the two groups of samples: (a) final strength, (b) yield point, (c) Young’s modulus, and (d) total inelastic strain after eight cycles under different confining pressures. Note that the results for both low and high confining pressures represent averages from two repeated experiments. Where shown, error bars denote \(\pm 1\) standard deviation from replicate tests at the same confining pressure; conditions tested only once are plotted without error bars.