Residual Strength and Fracture Energy from Plane-Strain Testing
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 126, Issue 10
Abstract
Field observations indicate that failure in soft rock is often associated with a slip surface or shear band, where deformation is concentrated in a narrow zone; displacements occur with decreasing stress within the shear band, whereas outside the band the material appears to be intact. In examining the propagation of the shear band, it is useful to establish the relation between shear stress and slip displacement. This was accomplished within a laboratory setting with a plane-strain compression apparatus, developed to study localized failure under controlled conditions. Tests on a soft rock, a sandstone with a uniaxial compressive strength of 10 MPa and a modulus of 2 GPa, were conducted to estimate fracture energy GIIC, a quantity used to evaluate energy dissipation of the failure process. GIIC was found to decrease by a factor of 3 when considering the actual displacements, rather than assuming tangential displacement only, that is, no displacement normal to the shear band. The experiments showed that the shear band was not completely formed until after peak strength and that sliding along the band during softening was associated with compaction; residual behavior exhibited virtually no volume change. The shear strength at peak stress was nonlinearly related to the normal stress, but the shear strength at the residual state displayed a linear relationship. For normal stresses less than the uniaxial strength, those typical of civil engineering practice, the response can be described as cohesion softening, with friction remaining constant in going from the peak to the residual stress states.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Bishop, A. W. ( 1971). “The influence of progressive failure on the choice of the method of stability analysis.” Géotechnique, London, 21(2), 168–172.
2.
Bjerrum, L. (1967). “Progressive failure in slopes of overconsolidated plastic clay and clay shales.”J. Soil Mech. and Found. Div., ASCE, 93(5), 3–49.
3.
Chowdhury, R. N. ( 1978). “Propagation of failure surfaces in natural slopes.” J. Geophys. Res., 83(B12), 5983–5988.
4.
Dawson, E. M., Roth, W. H., and Drescher, A. ( 1999). “Slope stability analysis by strength reduction.” Géotechnique, London, 49(6), 835–840.
5.
Drescher, A., Vardoulakis, I., and Han, C. ( 1990). “A biaxial apparatus for testing soils.” Geotech. Testing J., 13, 226–234.
6.
Duncan, J. M. (1996). “State of the art: Limit equilibrium and finite-element analysis of slopes.”J. Geotech. Engrg., ASCE, 122(7), 577–596.
7.
Finno, R. J., and Nerby, S. M. (1989). “Saturated clay response during braced cut construction.”J. Geotech. Engrg., ASCE, 115(8), 1065–1084.
8.
Finno, R. J., and Rhee, Y. ( 1993). “Consolidation, pre- and post-peak shearing responses from internally instrumented biaxial compression device.” Geotech. Testing J., 16(4), 496–509.
9.
Hvorslev, M. J. ( 1960). “Physical components of the shear strength of saturated clays.” Proc., Conf. Shear Strength of Cohesive Soils, ASCE, New York, 169–173.
10.
Labuz, J. F., and Bridell, J. M. ( 1993). “Reducing frictional constraint in compression testing through lubrication.” Int. J. Rock Mech. Min. Sci. and Geomech. Abstr., 30, 451–455.
11.
Labuz, J. F., Dai, S. T., and Papamichos, E. ( 1996). “Plane-strain compression of rock-like materials.” Int. J. Rock Mech. Min. Sci. and Geomech. Abstr., 33(6), 573–584.
12.
Palmer, C. A., and Rice, J. R. ( 1973). “The growth of slip surfaces in the progressive failure of over-consolidated clay.” Proc., Royal Soc., London, A332, 527–549.
13.
Read, R. S., and Martin, C. D. ( 1992). “Monitoring the excavation-induced response of granite.” Proc., 33rd U.S. Symp. Rock Mech., Balkema, Rotterdam, The Netherlands, 201–210.
14.
Rice, J. R. ( 1968). “A path independent integral and the approximate analysis of strain concentration by notches and cracks.” J. Appl. Mech., 35, 370–386.
15.
Rice, J. R. ( 1980). “The mechanics of earthquake rupture. Physics of the Earth's interior.” Proc., Int. School of Phys., Course LXXVIII, Italian Physical Society and North Holland Publishing, Amsterdam, 555–649.
16.
Skempton, A. W. ( 1964). “Long term stability of clay slopes.” Géotechnique, London, 14(2), 77–101.
17.
Vallejo, L. E. ( 1987). “The influence of fissures in a stiff clay subjected to direct shear.” Géotechnique, London, 37(1), 69–82.
18.
Vardoulakis, I., and Goldscheider, M. ( 1981). “Biaxial apparatus for testing shear bands in soils.” Proc., 10th Int. Conf. Soil Mech. Found. Engrg., Balkema, Rotterdam, The Netherlands, 819–824.
19.
Vardoulakis, I., and Sulem, J. ( 1995). Bifurcation analysis in geomechanics, Blackie Academic and Professional, Glasgow, U.K.
20.
Wong, T. F. ( 1982). “Shear fracture energy of Westerly granite from post-failure behavior.” J. Geophys. Res., 87(B2), 990–1000.
21.
Wong, T. F. ( 1986). “On the normal stress dependence of the shear fracture energy.” Proc., Earthquake Source Mech. 5th Maurice Ewing Symp., American Geophysical Union, Washington, D.C., 1–11.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 126 • Issue 10 • October 2000
Pages: 882 - 889
History
Received: Apr 13, 1999
Published online: Oct 1, 2000
Published in print: Oct 2000
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.