Cracking behaviors and strength of rock-like samples with steps of different geometries under shear stress Cracking behaviors and strength of rock-like samples with steps of different geometries under shear stress

最小化 最大化

Vol18 No.5: 1352-1370

Title】Cracking behaviors and strength of rock-like samples with steps of different geometries under shear stress

Author】LE Hui-lin1;. WEI Ji-hong1*; .SUN Shao-rui1; ZHANG Chu-chu2

Addresses】1 Department of Geology Engineering, Hohai University, Nanjing 210098, China; 2 China Energy Engineering Group Jiangsu Power Design Institute Co., Ltd., Nanjing 210098, China

Corresponding author】WEI Ji-hong

Citation】Le HL, Wei JH, Sun SR, Zhang CC (2021) Cracking behaviors and strength of rock-like samples with steps of different geometries under shear stress. Journal of Mountain Science 18(5). https://doi.org/10.1007/s11629-020-6443-2

DOI】https://doi.org/10.1007/s11629-020-6443-2

Abstract】Steps are distinctive features for estimating the movement of the upper and lower block of faults. However, studies about the influence of steps as a special type of discontinuity on cracking behaviors and strength of rock masses are limited. In this research, rock-like samples with steps and pre-existing flaws were fabricated. Step height h and the inclination angle of gentle slope of the step α were set to different values. Direct shear tests were conducted on these samples under different normal stresses. The experimental results reveal that the inclination angle of the gentle slope of the step α, step heighth, and normal stresshave an influence on the strength, crack initiation, and crack propagation of the samples. The experimental results show that crack behaviors and shear strength were affected by step inclination angles α and step height h. As the normal stress increases, the improvement of the strength of samples with a large step height is larger than that of samples with a small step height, the improvement of the strength of samples with α of 10° is larger than that of samples with α of 0° and -10°. The discrete element method was used to simulate the shear test. Numerical results show five different types of displacement vectors, which can be used to determine whether the cracks are tensile cracks or shear cracks. The above conclusions can provide help for estimating mechanical properties and failure modes of rock masses with steps of different geometries.

Keywords】Step; Preexisting flaw; Direct shear test; Crack behavior; Shear stress; Numerical test