@article{Zhang2022, 
author = {Ke Zhang and Guoli Luo and Kai Zhang},
title = {Study on the Mechanical Properties of 3D Printed Rock-Like Specimens Containing a Horizontal Flaw},
year = {2022},
journal = {Chinese Journal of Underground Space and Engineering},
volume = {18},
number = {6},
pages = {1834-1841},
keywords = {flaw, aperture, 3D printing, digital image correlation method, crack initiation stress, failure mode},
url = {https://www.sciopen.com/article/10.20174/j.juse.2022.06.010},
doi = {10.20174/j.juse.2022.06.010},
abstract = {In order to explore the influence of flaw aperture on the mechanical properties of fractured rock mass, the specimens containing a horizontal flaw were prepared by 3 D sand printing, and different flaw apertures were considered. The uniaxial compression tests were performed. The experimental phenomenon was explained from the perspective of stress distribution by using the finite element numerical simulation. The digital image correlation method was used to monitor the full-field deformation during loading with non-contact to quantitatively analyze the crack initiation, propagation and coalescence. The results show that: The mechanical properties of 3 D sand printing rock-like specimen are similar to those of natural rock, the experimental results also have well repeatability, and the variation coefficients of mechanical parameters are less than 0.046; the stress-strain curves of rock-like specimens with different flaw apertures are similar. The peak strength gradually decreases with the increase of flaw apertures and finally tends to be stable. A larger flaw aperture leads to a higher crack initiation stress. The crack firstly initiates in the middle of the pre-existing flaw, which is attributed to the maximum value of principal stress and corresponding distribution; the digital image correlation method was used to monitor the full-field deformation of the specimens during loading, progressive evolution of strain localization is observed in the process of deformation and fracturing, which reflects the law of crack initiation, propagation and coalescence. By calculating the displacement vector distribution around the crack propagation path, three types of displacement fields are identified: tensile, shear and tensile-shear mixed, it is found that the flaw aperture does not affect the failure mode of the specimens, which can be characterized by the tensile-shear mixed failure. This study can further improve understanding of the mechanical properties of fractured rock masses, and provides a reference for the application of 3 D printing technology in rock mechanics.}
}