Abstract The triaxial unloading tests of hard limestone are carried out. The mechanical properties changing with unloading stress path are studied. Five strength criteria are studied based on experimental results. Mohr-Coulomb criterion and Hoek-Brown criterion don?t describe the strength property of rock unloading failure. Drucker-Prager criterion and Mogi-Coulomb criterion fit experimental results very well. Mogi-Coulomb criterion fits experimental results better than Drucker-Prager criterion by comparison. The parabolic criterion is the best choice if the failure confining pressure is high. A rock unloading failure constitutive model is modified for describing the characteristic of volumetric strain. The theoretical model agrees well with experimental results.
|
Received: 19 May 2011
|
|
|
|