Journal article
Investigation on Mechanical Behaviors of Sandstone with Two Preexisting Flaws under Triaxial Compression
Rock mechanics and rock engineering, Vol.49, pp.375-399
02/2016
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Abstract
Triaxial compression experiments on sandstone samples with two preexisting closed non-overlapping flaws were performed to investigate the deformation and strength behaviors. Three types of preexisting closed flaw pair in sandstone samples, i.e., parallel low-dip (type B), parallel high-dip (type C), and composite high- and low-dip (type D), were considered as the typical arrangements of the non-overlapping crack pair. A general rule has been found that the arrangement of the flaw pair has greater impact on the rock deformation, strength, and crack coalescence pattern than the confining pressure (5-20 MPa). Experimental results showed that, compared with intact sandstone samples, the postpeak stress-strain curves of flawed samples distinctly demonstrate stress fluctuation. In particular, the unique prepeak stress-strain curves of the specimens with a low-dip flaw pair (type B) present oblique Z-shape with a double-peak stress. The stress for crack initiation sigma (ci), the critical stress of dilation sigma (cd), and the peak strength sigma (c) of precracked sandstone samples are significantly lower than those of intact rock. The present numerical study, which is an extension of the test analysis, focuses on identifying the crack nature (tensile or shear) and coalescence process. These simulated crack coalescence patterns are in good agreement with the laboratory test results. The cracks of the precracked samples that contained flaws with small inclination angle (associated with either type B or type D) generally initiate at the inner flaw tips and eventually lead to simple direct shear coalescence. However, complex indirect shear coalescence appears in the model containing a steep preexisting flaw pair (associated with type B specimen), even though no coalescence occurs when sigma (3) = 5 MPa.
Details
- Title
- Investigation on Mechanical Behaviors of Sandstone with Two Preexisting Flaws under Triaxial Compression
- Creators
- Da Huang - Chongqing UniversityDongming Gu - Chongqing UniversityChao Yang - Chongqing UniversityRunqiu Huang - Chengdu University of TechnologyGuoyang Fu - University of Western Australia
- Publication Details
- Rock mechanics and rock engineering, Vol.49, pp.375-399
- Publisher
- Springer Nature
- Number of pages
- 25
- Grant note
- 41172243; 41472245; 41130745 / National Natural Science Foundation of China; National Natural Science Foundation of China (NSFC) CYB14018 / Chongqing Graduate Student Research Innovation Project 106112014CDJZR200009 / Fundamental Research Funds for the Central Universities
- Identifiers
- 991013126109902368
- Copyright
- (c) Springer-Verlag Wien 2015.
- Academic Unit
- Faculty of Science and Engineering
- Language
- English
- Resource Type
- Journal article