Issue 30

L. Zhang et alii, Frattura ed Integrità Strutturale, 30 (2014) 515-525; DOI: 10.3221/IGF-ESIS.30.62 523 0 20 40 60 80 100 120 140 0.000 0.002 0.004 0.006 0.008 0.010 0 20 40 60 80 100 120 140 160 0.000 0.003 0.006 0.009 0.012 (a) (b) 0 30 60 90 120 150 180 0.000 0.003 0.006 0.009 0.012 0 40 80 120 160 200 0.000 0.005 0.010 0.015 (c) (d) Figure 9 : Stress-strain curves of conventional triaxial tests: (a) Confining pressure 10 MPa; (b) Confining pressure 20 MPa; (c) Confining pressure 30 MPa; (d) Confining pressure 40 MPa. (a) (b) (c) Figure 10 : Stress-strain curves of different unloading rates: (a) Unloading rate of confining pressure 0.2 MPa/s; (b) Unloading rate of confining pressure 0.4 MPa/s; (c) Unloading rate of confining pressure 0.8 MPa/s.     1 [MPa]  1 [MPa]  1 [MPa]  1 [MPa]    1 [MPa]    1 [MPa]  1 [MPa]