Studies On Damage Evolution Characteristics In Non-interpenetrated Material Under Axial Compressive Condition

The mechanical properties of the non-interpenetrated jointed rock mass, as a common engineering materials, are the basic considerations in rock mechanics and engineering. Many researches focus on the rock mass with interpenetrated joints, few has been known on the study of rock mass with non-interpenetrated cracks. In this paper, rock-like material samples with different obliquity and number non-interpenetrated cracks are tested on MTS, sound wave testing devices and CT devices. And systematic researches are also done failure pattern, deformation, strength and micro-damage evolution law under axial compressive condition for the non-interpenetrated crack samples. The relationships among deformation, strength, failure pattern and obliquity, the number of non-interpenetrated cracks is further obtained by the sound wave testing during loading in the MTS test. Interior crack evolution law during the failure process is proposed through analyzing the CT images and reformed three-dimension CT images. The micro-damage evolution properties are finally studied by analyzing the relationship between the stress level, the gray-scale of CT image and the damage isoline of the scanning image. Based on the analysis of relationship between damage evolution of crack and evolution of micro-crack, singularity damage variable and distribution damage variable have been defined, which can illustrate two kinds of damage, the damage constitutive equation of non-interpenetrated crack material under axial compressive condition has been built and validated by tests. Based on the fractal geometry theory, the fractal characteristics of the damage evolution are analyzed, and the localized damage parameter is defined through the relationship between the damage development fractal dimension and the stress.