scholarly journals Numerical simulation of damage characteristics of jointed rock under blasting load

2021 ◽  
Vol 861 (7) ◽  
pp. 072136
Author(s):  
Jianhang Du ◽  
Tao He ◽  
Yonglin Xiong ◽  
Rongyue Zheng
Keyword(s):  
Numerical Simulation ◽  
Jointed Rock ◽  
Damage Characteristics ◽  
Blasting Load

scholarly journals Study on Shear Mechanism of Bolted Jointed Rocks: Experiments and CZM-Based FEM Simulations

2019 ◽  
Vol 10 (1) ◽  
pp. 62 ◽  
Author(s):  
Shubo Zhang ◽  
Gang Wang ◽  
Yujing Jiang ◽  
Xianlong WU ◽  
Genxiao Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Failure Mechanism ◽  
Laboratory Experiments ◽  
Shear Failure ◽  
Cohesive Zone Model ◽  
Rock Fracture ◽  
High Strength ◽  
Simulation Method ◽  
Jointed Rock ◽  
Zone Model

Based on the underground jointed rock of the Huangdao water sealed oil depot in China, the shear failure mechanism of bolted jointed rock is studied through laboratory experiments and numerical simulation. Laboratory experiments are performed to explore the shear behavior of bolted jointed rock with different joint roughness. Our results show that using high strength bolts is beneficial to improving the shear strength of the jointed rock, but the high strength of bolts can also lead to the rock fracture, which should be avoided. For this particular project site, experimental results indicate that 15% elongation is the best. In addition, a new numerical simulation method with CZM (cohesive zone model) used for modeling the shearing process of bolted jointed rock is proposed. It can reasonably describe the characteristics of jointed rock as a discontinuous medium, and bolt as a continuous medium, that replicate well the shearing process. The numerical model is then verified by comparing the experiment results, and it can be effectively be applied to the simulation of joint shearing process. Finally, we use this simulation method to explore the shear failure mechanism of bolted joints, and find that the root cause of rock failure is the deformation mismatch between the bolt and the surrounding rock. The tensile stress between them eventually causes the rock to fracture near the bolt hole.

Numerical simulation of fracture characteristics of jointed rock masses under blasting load

2019 ◽  
Vol 36 (6) ◽  
pp. 1835-1851 ◽  
Author(s):  
Chao Liu ◽  
Mingyang Yang ◽  
Haoyu Han ◽  
Wenping Yue
Keyword(s):  
Jointed Rock ◽  
Rock Masses ◽  
The Finite Element Method ◽  
Practical Application ◽  
Fracture Characteristics ◽  
Content Type ◽  
Jointed Rock Masses ◽  
Calculation Results ◽  
Damage Theory ◽  
Blasting Load

Purpose To study fracture characteristics of jointed rock masses under blasting load, the RFPA2D analysis software for dynamic fracture of rocks based on the finite element method and statistical damage theory was used. Design/methodology/approach On this basis, this research simulated the fracture process of rock masses in blasting with different joint geometrical characteristics and mainly analysed the influences of distance from joints to blasting holes, the length of joints, the number of joints and joint angle on fracture of rock masses. Findings The calculation results show that with the constant increase of the distance from joints to blasting holes, the influences of joints on blasting effects of rock masses gradually reduced. Rock masses with long joints experienced more serious damages than those with short joints. Damages obviously increased with the changing from rock masses without joints to rock masses with joints, and when there were three joints, the further increase of the number of joints had unobvious changes on blasting effects of rock masses. Joints showed significant guidance effect on the propagation of cracks in blasting: promoting propagation of main vertical cracks deflecting to the ends of joints. Originality/value The research results are expected to provide some theoretical bases in practical application of engineering blasting.

scholarly journals Parallel Offset Crack Interactions in Rock under Unloading Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Zihan Zhou ◽  
Zhonghui Chen
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Inclination Angle ◽  
Shear Failure ◽  
Superposition Principle ◽  
Interaction Strength ◽  
Jointed Rock ◽  
Interaction Coefficient ◽  
Open Pit ◽  
Type I

Rock slopes contain numerous nonpenetrating intermittent joints which maintain stability under excavation disturbance. The tip interaction coefficient (IC) of parallel offset double cracks in a typical rock mass under unloading conditions was calculated in this study based on the superposition principle and fracture mechanics to determine the meso-influence law of intermittent joint interaction in the slope under the action of excavation. The influence of many factors on the said interaction was also analyzed theoretically. Lateral unloading tests were conducted on rock-like specimens with parallel offset cracks in addition to RFPA2D numerical simulation and theoretical analysis. The results show that a smaller length of rock bridge or staggered distance between the cracks results in more severe and sensitive interactions at the crack tip. The Type I interaction strength of the tip of the crack is not affected by the inclination angle of the crack, but shear failure gradually weakens as the angle changes. The shear failure of the tip of the crack is more sensitive to changes in the inclination angle when the cracks are closer to each other; the change is the most intense when α is about 60°. Lateral unloading test and RFPA2D numerical simulation results are in close agreement with the theoretical analysis, which validates the theoretical results. The current study shows the interaction of the parallel offset cracks in rock under unloading conditions and is conducive to the study of the meso-failure mechanism of the jointed rock slope in an open-pit mine under the action of excavation.

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