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Mesoscopic mechanical properties of rock-like material containing two circular holes under uniaxial compression |
ZHOU Yu1,LIU Bing1,WANG Li2,LI Xiang1,DING Yinping3 |
(1. Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine,University of Science and Technology Beijing,Beijing 100083,China;2. PowerChina Road Bridge Group Co.,Ltd.,Beijing 100048,China;3. China Railway
16th Bureau Group Co.,Ltd.,Beijing 100018,China) |
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Abstract As a kind of typical flaw,circular hole plays a significant role on the mechanical properties of rock. Specimens containing two circular holes were constructed and subjected to uniaxial compression based on lab experiment and two dimensional particle flow code(PFC2D). The effect of the distance between holes and the dip angle on the strength,fracture mode and crack development of rock were investigated in detail. With the increase of the dip angel,the uniaxial compressive strength of specimens decreases first then increases. The uniaxial compressive strength reaches the minimum value when the dip angle equals to 45° to 60°. When the dip angle equals to 90°,the uniaxial compressive strength of specimen increases first and then decreases with the increase of the distance between the holes,and reaches the maximum value when the distance between holes equals to 40 mm approximately. The fractures generated in the specimen can be classified into three modes,namely mode I (tensile fracture),mode II (shear fracture) and mode III (mixed fracture). When the distance between the holes is small,with the increase of dip angle,the fracture mode between the holes changes from mode III to mode II gradually, while on the hole walls adjacent to loading part, mode I fracture occurs. However,mode II fracture always occurs on the hole walls adjacent to the side boundaries of specimen. When the dip angle equals to 90°,the interaction between two holes weakens with the increase of the distance between holes,however,the mode I fracture occurs on the hole walls adjacent to loading part and the mode II fracture occurs on the hole walls adjacent to the side boundaries all the time. The mode II fracture firstly initiates on the rock bridge between two holes,and then mode I fracture generates on the hole walls adjacent to loading part,and finally mode II fracture occurs on the hole walls adjacent to the side boundaries. Generally,the magnitude of acoustic emission (AE) from the mode I fracture is higher than that from the mode II fracture.
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