Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Abstract

e strength and failure characteristics for granite specimen with a set of cross-joints of different lengths were studied using PFC 2D software. e results show that when the included angle of α between the main joint and loading direction is 30°or 45°, no matter what the included angle of β between main and secondary joints is, the main joint controls crack propagation and failure of granite specimen, which occurs the shear failure propagating from main joint tips, and the corresponding uniaxial compressive strength is low. Meanwhile, the secondary joint is the key joint for crack propagation and failure at α of 0°and 90°except when β is 90°. e granite specimen occurs the shear failure propagating from secondary joint tips. And, the shear failure crossing upper tips of main and secondary joints is found at α of 0°or 90°and β of 90°. eir uniaxial compressive strengths are large. Also, the combined actions of main and secondary joints determine crack propagation and failure at α of 60°except when β is 90°. e granite specimen occurs the hybrid failure, including shear failure propagating from main joint tips and tensile failure propagating from main and secondary joints center or secondary joint tips. And, when α is 60°and β is 90°, the granite specimen occurs the shear failure along secondary joint plane direction, and its uniaxial compressive strength is small. Generally, when α or β is a fixed value, the uniaxial compressive strength firstly decreases and then increases with the increase of β or α. Additionally, when α is 60°and β > 45°, the uniaxial compressive strength represents a decreasing trend. e uniaxial compressive strength at α and β between 30°a nd 60°is generally small. Finally, the microdisplacement field distributions of granite specimen were discussed.

Stability of Close Chambers Surrounding Rock in Deep and Comprehensive Control Technology

“…e specific section and location of each chamber are shown in Figure 1(b). [19]. e compressive and elastic deformation stages of rock samples before achieving peak strength were similar, and the yield stages were different.…”

Crack Initiation Behaviors of Granite Specimens Containing Crossing‐Double‐Flaws with Different Lengths under Uniaxial Loading

“…Appropriate microparameters should be selected before modeling through a calibration process. Due to the limitation of laboratory test conditions, the microparameters (Table 1) of granite specimen provided by Yin et al [38] and Zhang et al [39] were used to carry out the numerical tests, which were described in detail as follows. Young's modulus of the particle and parallel bond modulus are 3 GPa and 43 GPa, respectively.…”

“…In nature, the rock mass may contain one or more sets of crossing-double-flaws [31,[36][37][38]. e strength and failure characteristics of rock specimens containing a set of crossing-flaws [31,38] and two sets of crossing-flaws [36,37] were studied, respectively. ere are few studies on the crack initiation behavior of rock specimen containing crossingflaws.…”

Point Load Test of Half‐Cylinder Core Using the Numerical Model and Laboratory Tests: Size Suggestion and Correlation with Cylinder Core

“…At the same time, in order to reduce the complexity of the DEM micromechanical parameter calibration, we selected three kinds of rock as shown in Table 1 (number 2 porphyritic granodiorite, number 3 granodiorite, and number 10 granodiorite porphyry) as the calibration objects. e DEM [28] of structures in rock or soil required calibration of the FJM parameters of materials using UCS tests [2,[32][33][34][35][36][37][38]. To simulate rocks with different UCS and PLSI, the tensile strength and cohesion of the FJM parameters were varied, while other parameters were kept constant.…”