考虑裂纹闭合效应的岩石损伤本构关系

岩石中的预存裂纹只有在一定的法向压应力即裂纹闭合应力的作用下才可能闭合，其闭合过程与其方位和外加应力场有关，并且，即使对于裂纹已经完全闭合的岩石，如果裂纹闭合应力不同，则岩石的应力应交关系也不相同。本文建立了考虑裂纹闭合效应的岩石细观损伤力学模型，分析了裂纹闭合应力对岩石损伤演化过程和应力应变关系的影响。数值结果表明裂纹闭合应力显著地改变岩石的应力应变关系，表现为随裂纹闭合应力的增加，岩石的轴向应变变化较小，侧向应变和体积应变则大为增加。

The Effect of Crack Closing Streses on the Damage Constitutive Relation for Rock

The preexisting cracks in rock can not be closed unless their normal compressive stresses reach acertain value or crack closing stress.The closing process of preexisting cracks is dependent on the externally compressive loadings and their orientations. Furthermore, even though the preexisting cracksin rocks have become all close, the rocks with different crack closing stress would not have the identical damage constitutive relation. The paper develop a micromechanical damage medel for rock withcrack closing response. The effect of crack closing stress is analyzed on the damage evolution and thestress-strain relation of rock. The numerical results indicate that crack closing stress has a significantinfluence on the stress strain relation. It is shown that both the lateral strain and the volumetric strainof rock increase greatly with the raise of the crack closing stress.