Analysis of Crack Propagation Characteristics of Rock-like Material with Double Closed Cracks Under Uniaxial Compression
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ORIGINAL PAPER
Analysis of Crack Propagation Characteristics of Rock-like Material with Double Closed Cracks Under Uniaxial Compression JiMing Zhu . Hailing Yu
Received: 10 June 2020 / Accepted: 28 June 2020 Ó Springer Nature Switzerland AG 2020
Abstract In order to explore the influence of the length and dip angle of the rock bridge on crack initiation, propagation and coalescence, based on the rock-like material uniaxial compression laboratory test, the particle flow program PFC2D was used to simulate the uniaxial compression of rock-like specimens with double prefabricated closed cracks, and the strength characteristics and crack propagation and coalescence laws of specimens with different prefabricated closed cracks were obtained. The numerical results showed that: Changing the length of the rock bridge and keeping the dip angle constant, when the length of the rock bridge was 13 mm, the double cracks had 2 penetrations, and the other lengths had only 1 penetration. As the length of the rock bridge increased, the peak stress appeared to increase first and then decrease, while the crack initiation stress did not change much. Changing the dip angle of the rock bridge and keeping the length constant, when the rock bridge dip angle was - 75° and - 15°, there were 3 penetrations; when the rock bridge dip angle was - 45°, there were 4 penetrations; when the rock bridge dip angle was 15°, 45° and 75°, only 1 J. Zhu College of Resources, Shandong University of Science and Technology, Taian 271019, China H. Yu (&) College of Mechanical and Architectural Engineering, Taishan University, Taian 271000, China e-mail: [email protected]
penetration was formed. As the dip angle of the rock bridge increased, the peak stress appeared to increase first and then decrease and then increase, and the crack initiation stress appeared to decrease first and then increase. Keywords Uniaxial compression Particle flow Closed crack Crack propagation Crack coalescence
1 Introduction Fractured rock mass is a complex engineering geological body, and the coalescence of the existing cracks in it will cause different degrees of damage or even destruction to the rock mass. Therefore, it is of great practical significance to further study the propagation and coalescence laws of cracks in rock mass. In order to explore the laws of crack propagation and coalescence of specimens with double cracks, many scholars had carried out a large number of physical experiments. Wong and Chau (1998) conducted a uniaxial compression test for sandstone with double cracks, and analyzed the effects of crack dip angle and rock bridge dip angle on the crack aggregation mode; Zhao et al. (2016) conducted a uniaxial compression test for rock-like material with parallel double closed cracks, and analyzed the effect of rock bridge ligament angle on the local strain concentration at the crack tip; Zhang et al. (2017a, b) conducted a triaxial
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Geotech Geol Eng
compression test of rock-like material with p
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