Effect of intermediate principal stress and loading-path on failure of cementitious materials using granular micromechanics

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• 作者：Payam Poorsolhjouy ; Anil Misra ; ^{amisra@ku.edu}
• 关键词：Granular micromechanics ; Cementitious materials ; Failure ; Load-path dependence ; Multi-axial loading
• 刊名：International Journal of Solids and Structures
• 出版年：2017
• 出版时间：1 March 2017
• 年：2017
• 卷：108
• 期：Complete
• 页码：139-152
• 全文大小：2895 K
• 卷排序：108

文摘

The failure behavior of rock-like cemented granular materials shows dependency upon both the intermediate principal stress as well as the loading path. Here, we apply a thermo-mechanics based granular micromechanics constitutive relationships of cementitious materials to predict such failure phenomena and investigate the macro- and the micro-scale mechanisms that govern the predicted behavior. True triaxial tests with different levels of minor and intermediate principal stress are simulated. The simulations clearly show that for a given loading path, the maximum principal stress at failure depends upon both the minor and the intermediate principal stress components in a manner that conform closely with recent experimental observations. The path dependent nature of the material response to loading is also demonstrated in the failure behavior by simulations performed for two different types of true triaxial loading paths. The macro-scale failure mechanisms are investigated using the eigenvalues of the tangent stiffness matrix which indicate the corresponding Kelvin mode at failure. From microscopic viewpoint, the evolution of normal and tangential components of inter-granular force vectors is analyzed to reveal the inter-granular mechanisms associated with the load bearing and failure. With respect to the localized failure modes, the eigenvalue analysis of the localization tensor is performed and the direction of failure plane is studied. The direction of failure plane is seen to depend on all component of the principal stress. Further, the results show a change in the localized macro-scale failure mechanism from shear dominated at low confinement to a mixture of shear and compaction at higher confinement, which agrees with the decreasing trend observed in fault angle by increasing confinement. This result is in agreement with experimental results of true triaxial tests on rock samples which report similar transition from shear to compaction bands.