Experimental Study on Bedding Plane Interfacial Slip

2012 ◽  
Vol 256-259 ◽  
pp. 298-301
Author(s):  
Shu Hong Dai ◽  
Ying Sun ◽  
Zi Xian Dong

Interfacial slip in rock was studied utilizing digital image correlation method (DICM). Notched rock specimens consisting of a natural interface under three point bending were employed for researching the characters and mechanisms of the interfacial slip. The displacement and strain fields on the surface of specimen were measured accurately by DICM. The experimental results show that the interfacial slip can change the crack extension direction and mode. The results are helpful in researching the mechanism of interfacial slip and practical applications in rock fracture problems.

2019 ◽  
Vol 2019 ◽  
pp. 1-20
Author(s):  
Zhidong Wang ◽  
Liyun Li ◽  
Bingquan Liu ◽  
Chuang Han ◽  
Tianxiang Lan

Based on the existing classification research of rockburst dynamic disasters, a new rockburst model is introduced. The model specimens with inclusion rock are designed and produced, and the indoor test of inclusion rockburst with or without cementation, different inclusion angles, and prefabricated cracks of different lengths is carried out. The failure process and displacement variation of rock specimens are recorded and measured by the high-speed camera system and digital image correlation method, and based on this, the characteristics and laws of rockburst are analyzed. The results show that the failure process of inclusion rock can be divided into several periods, such as crushing and extrusion of the cement body, and the cracks in the upper left tip, the lower right tip, the lower left tip, and the upper tip are expanded and broken in different orders. The dynamic ejection failure of the rock fragments occurs when the degree of failure is severe, and the static failure occurs when the degree of failure is weak. The inclusions have cementation, and the better the cementation, the greater the stress loading required in the failure, the greater the energy accumulated, the more severe the failure, and the higher the fractal dimension of the fragments. The larger the angle of the inclusion tip, the greater the stress loading in failure; the greater the change of the u and v displacements, the more the displacement of the inclusions changed; and the more the energy accumulated, the higher the fractal dimension of the fragment. The smaller the crack length, the greater the stress loading in failure, and the more the energy accumulated, the higher the fractal dimension of the fragments in failure. With more number of cracks and the more severe expansion before failure, the failure of rock mass can be transformed from the dynamic to the static.


Clay Minerals ◽  
2013 ◽  
Vol 48 (2) ◽  
pp. 391-402 ◽  
Author(s):  
L. L. Wang ◽  
M. Bornert ◽  
S. Chanchole ◽  
D. S. Yang ◽  
E. Héripre ◽  
...  

AbstractAn experimental study of the swelling anisotropy of the Callovo-Oxfordian argillaceous rock under hydration is presented. The investigation, which combines environmental scanning electron microscopy (ESEM) and digital image correlation techniques, has been carried out at the micrometric scale of the composite microstructure of the rock. Specimens were hydrated in the ESEM over a wide range of relative humidity and observations conducted on two planes: plane 1 parallel to the bedding plane, and plane 2 perpendicular to it. The observations reveal that the local swelling (which can be quantified at a local gauge length of about 5 μm) is strongly anisotropic in both planes. The global swelling, measured over areas of about 500 μm in width, is also clearly anisotropic in plane 2 (with major swelling direction normal to the bedding plane), but not in plane 1. The global isotropy in plane 1 arises from the uniform distribution of the orientation of anisotropic local strains, while the anisotropic swelling in plane 2 is due to a preferred local orientation.


2014 ◽  
Vol 611 ◽  
pp. 490-495
Author(s):  
Martin Schrötter ◽  
Martin Hagara ◽  
Matúš Kalina

The aim of this article is to present the influence of stochastic pattern on results accuracy of digital image correlation method in plastic areas. The various types of stochastic patterns were applied on testing specimens which were then tensioned. There was correlated the intensity of black and white color (denoted as grey value) dispersed on a specimen, then the mean value of estimated error for unloaded state as well as state of highest measured deformation and finally the amount of non-correlated facets. Also the maximal deformation of specimens was compared by which the damage of stochastic pattern emerged.


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