(a) AE rate (RDC/min) and (b) b-value plotted against shear strain rate (per min) relationships (linear regressions) obtained from drained triaxial shearing tests at effective confining pressures of 300 kPa performed on LBS 1·0–2·0 and LBS 0·25–3·35 at axial displacement rates of 1, 3 and 6 mm/h (tests 9, 10, 11 and 15)