不同应力路径大理岩物理力学参数变化规律

Study on the Physical-mechanical Parameters of Marble under Different Stress Paths

基于大理岩常规三轴加荷与卸荷试验结果,分析加卸荷应力路径下大理岩各阶段特征应力、黏聚力c、内摩擦角φ在变形破坏中的变化规律。试验结果表明,相同卸荷速率条件下,压密应力对应的环向应变、体积应变随围压的增大而减小,起裂应力及扩容应力随围压增大而增大,加卸荷应力路径下扩容应力对应的环向应变均稳定在(-0.000 4±0.000 1)范围内。大理岩卸荷破坏的初始屈服面和后继屈服面均符合Mogi-Coulomb函数形式,峰值强度前黏聚力c随塑性参数εps的增大而减小,内摩擦角φ随塑性参数εps的增大而增大。

Based on the results of the marble conventional triaxial load and unload tests, variations of the charac- teristic stress, cohesive force, internal friction angle are proposed in the rock deformation process of load and unload stress paths. Experimental results revealed that, hoop strain and volumetric strain corresponding to the compaction stress became smaller under the same unload rate with the increase of the confining pressure. But the crack initiation stress and expansion stress became larger. The hoop strain corresponding to expansion stress were stabled in the range of （-0.000 4±0.000 1 ）. Initial yield surface and subsequent yield surface conformed to Mogi-Coulomb functional form in unload stress path. The cohesive force c decreased and the internal friction angle increased with the increase of plastic parameter （ p~ before the peak strength.