脆性岩石真三轴能量强度准则研究

Study of triaxial energy strength criterion for brittle rock materials

基于岩石材料拉压强度不等和中间主应力对强度影响特点,从可释放弹性能角度出发推导和建立了可考虑中间主应力对岩石破坏弹性能释放影响的真三轴能量强度准则,利用厚壁圆筒试验数据和已有文献真三轴试验数据以及从能量准则参数物理含义三方面分析验证了所建真三轴能量强度准则的合理性及可靠性.结果表明,所建真三轴能量准则能适应于厚壁圆筒及真三轴压力试验的多种复杂应力状态;花岗岩、石灰岩中间主应力影响大于红砂岩、中细砂岩;对同种岩石来说,岩石中间主应力影响系数随应力状态不同而不同,总体变化趋势随中间主应力增加而先增大后减小;岩石能量强度准则与岩石应力状态和材料物理性质密切相关.

Based on rock properties of unequal compression and tensile strengths and the strength influence of intermediate principal stress, from the viewpoint of releasable elastic en ergy, a rock triaxial energy strength criterion taking account of the influence of intermediate principal stress on elastic energy release after rock failure was deduced and set up. The rationality and reliability of the proposed strength criterion was further validated by a lot of testing data from thick-walled rock cylinder experiments and rock true triaxial experiments in pub- lished literatures and also analyzed from the physical implications of strength criterion parame- ters. Research results show that the proposed triaxial energy strength criterion can be suitable for various complex stress states in thick-walled rock cylinder experiments and rock true triaxi- al experiments. The influence of intermediate principal stress for granite and limestone is heav ier than that of red sandstone and middle-fine sandstone; as for the same kind of rock materi als, the influence coefficient of intermediate principal stress is varied with stress states, the general variation trend is that the influence coefficient is increased and then decreased with the development of intermediate principal stress. Rock energy strength criterion is in close correla- tion with stress states and rock material physical properties.