Measurements plotted against shear strain (%) from a drained triaxial shearing test performed on LBS 0·25–3·35 at an effective confining pressure of 300 kPa and axial displacement rates of 1, 3 and 6 mm/h (test 15): (a) deviator stress (kPa); (b) volumetric strain (%) (dilation shown as positive); (c) AE rate (RDC/min); (d) b-value; (e) AE generated per increment of boundary work (RDC/J)