Parallel Offset Crack Interactions in Rock under Unloading Conditions

Zhou, Zihan; Chen, Zhonghui

doi:10.1155/2019/1430624

Cited by 7 publications

(2 citation statements)

References 21 publications

(19 reference statements)

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“…e composite coal-rock samples are essentially combinations of soft and hard phases, so their mechanical properties must be different from that of single coal or rock. Zhou et al studied the interaction of rock cracks under unloading conditions, which showed that the change of crack angle would weaken shear failure [6]. Qin et al studied the energy evolution and acoustic emission law of sandstone under unloading conditions [7].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Triaxial Unloading Failure of Deep Composite Coal‐Rock

Yang

et al. 2021

Advances in Civil Engineering

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With the deep mining of coal, the phenomenon of high ground stress is more likely to cause dynamic disaster. In view of the above problems, this paper takes the unloading process of coal mining as the background to study the effects of mining rates under different conditions on the mechanical properties and triaxial failure criterion of composite coal-rock, so as to provide a theoretical basis for the prevention and control of dynamic disasters in coal mines. The composite coal-rock models with a composite ratio of 1 : 1 : 1 were tested under different unloading rates or confining pressures. The results show that the triaxial unloading process of coal-rock can be divided into five stages: compaction, single elasticity, elastic-plastic unloading, partial fracture, and complete fracture. In this paper, the failure criterion of composite coal-rock triaxial unloading is derived. The unloading rate has an exponential relationship with the triaxial compressive strength, and the relationship between initial confining pressure and compressive strength is linear. The triaxial compressive strength is determined by both. The peak strains ε of all samples under different unloading conditions were around 0.01. And initial confining pressure had an influence on the strain variation trend during the unloading of composite coal-rock. The higher the initial confining pressure, the greater the elastic modulus. In addition, an increase of initial confining pressure led to the increase of the total energy converted into dissipated part in the process of fracture and caused the obvious increase of the rebound characteristics of the curve. However, the unloading rate had no influence on the strain trend.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Triaxial Unloading Failure of Deep Composite Coal‐Rock

Yang

et al. 2021

Advances in Civil Engineering

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“…There have been many other valuable contributions to the literature. Zhou and Chen [10] studied the parallel crack interactions in rock under unloading conditions based on fracture mechanics and found that a smaller length of rock bridge or staggered distance between the cracks results in more severe and sensitive interactions at the crack tip. Zou et al [11] performed the research of cracking processes in a natural rock under dynamic loading conditions and found that only the antiwing and shear patches evolve into two symmetrical pairs of shear cracks, which result in the specimen failure under dynamic compression.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Dynamic Responses of Rock Containing Parallel Cracks under Combined Dynamic and Static Loading

Zhou

Chen

2020

Geofluids

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Open-pit slopes contain numerous nonpenetrating, intermittent joints which maintain stability under blasting operations. The tip dynamic response coefficient (DRC) of parallel cracks in a typical rock mass under combined dynamic and static loading conditions was calculated in this study based on the superposition principle. The dynamic response law of the intermittent joint in the slope under blasting was determined accordingly. The influence of many factors (the disturbance amplitude of dynamic load, the lateral confining pressure, the length of rock bridge, the length between cracks, the staggered distance between cracks, and the crack inclination angle) on the dynamic response was theoretically analyzed as well. The ABAQUS numerical assessments were conducted on simulation models with parallel cracks under combined dynamic and static loading conditions. The results show that a larger dynamic load amplitude and smaller crack inclination angle/confining pressure result in greater Type II dynamic strengthening effect on the crack tip. When the length of the rock bridge between cracks (s) is smaller than the half length of the crack (a), the dynamic strengthening effect at the crack tip weakens gradually with increase in s; whens/a≥1, the strengthening effect is almost unchanged. With the increase in the staggered distance between cracks (h), the dynamic strengthening effect of the crack tip weakens at first and then strengthens; the strengthening effect is weakest when h/a=0.4; the crack propagation under combined dynamic and static loading is the most sensitive to the lateral confining pressure (σ3) and is the least sensitive to the inclination angle of the cracks (α). Theoretical results are validated by comparison with numerical simulation results. Such information regarding the dynamic response law of the parallel cracks in rock masses under dynamic and static loading conditions is conducive to further research on the mesofailure mechanism of open-pit mine jointed rock slopes under blasting operations.

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Fracture of brittle material with two 3D parallel internal cracks under thermal stress: Experimental and numerical analysis

Wang

Xi-nan

et al. 2023

Engineering Fracture Mechanics

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Parallel Offset Crack Interactions in Rock under Unloading Conditions

Cited by 7 publications

References 21 publications

Experimental Study on Triaxial Unloading Failure of Deep Composite Coal‐Rock

Experimental Study on Triaxial Unloading Failure of Deep Composite Coal‐Rock

Numerical Analysis of Dynamic Responses of Rock Containing Parallel Cracks under Combined Dynamic and Static Loading

Fracture of brittle material with two 3D parallel internal cracks under thermal stress: Experimental and numerical analysis

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