Analysis of uniaxial compression of rock mass with parallel cracks based on experimental study and PFC2D numerical simulation
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1
College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu, 610059, PR China
2
Geotechnical Engineering Department, Nanjing Hydraulic Research Institute, Nanjing, Jiangsu Province, 210029, PR China
3
School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, PR China
4
Department of Earth Sciences, University of Delaware, Delaware 19716, United States
Submission date: 2021-03-30
Final revision date: 2021-07-27
Acceptance date: 2021-07-27
Publication date: 2022-03-30
Archives of Civil Engineering 2022;68(1):111-128
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ABSTRACT
In this study, the uniaxial compression test and the numerical simulation of the twodimensional particle flow code (PFC2D) were used to study the mechanical properties and failure laws of rock masses with parallel cracks. The experiment considers the influences of crack length (��º, crack angle (��1, ��2), and numerical changes in the rock bridge length (ℎ) and bridge angle (��) on failures of rock-like specimens. The results indicate that the uniaxial compressive strength (UCS) of the rock-like specimens with parallel cracks decreases with increasing �� under different �� values. The smaller angle between the preset crack and the loadinging direction (��) resulting in higher UCS. In addition, a larger ℎ results in higher UCS in the specimen. When ��1 or ��2 is fixed, the UCS and elastic modulus of the specimen show an ‘M’ shape with an increase in ��. Moreover, the crack growth or failure mode of samples with different �� values is similar. When ��1 or ��2 is small, the failure of the specimen is affected by the development and expansion of wing cracks. If one of ��1 and ��2 is large, the failure of the specimen is dominated by the expansion and development of the secondary cracks which is generated at the tip of the prefabricated crack. Furthermore, when the angle between the prefabricated crack and the loading direction is ��1 = 0°, the rock bridge is less likely to reach penetration failure as ℎ increases. Secondary crack connections between the prefabricated cracks occur only when �� is small. When �� ¡ 30°, the failure mode of the specimen is crack tip cracking which leads to penetration failure of the specimen, or the overall splitting failure.