Effect of Static Loading on Rock Fragmentation Efficiency Under Ultrasonic Vibration

Zhou, Yu; Yin, Songyu; Zhao, Dajun

doi:10.1007/s10706-019-00814-3

Cited by 14 publications

(4 citation statements)

References 28 publications

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“…Zhao et al studied rock breaking under the static-dynamic coupling, and the results show that the combined loading mode can significantly improve the effect of rock-breaking [27]. Zhou et al studied the effect of static load on the intrinsic frequency of granite under ultrasonic vibration and obtained that the intrinsic frequency increases logarithmically with the magnitude of the static load [28].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Simulation Study on Breaking Rock under Coupled Static Loading and Ultrasonic Vibration

Zhao

Zhang

et al. 2022

Shock and Vibration

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In recent years, ultrasonic vibration rock-breaking technology has aroused great interest in tunnel excavation and underground mineral. To apply this technology to practical engineering, it is necessary to compare the difference between cumulative damage and crack propagation of rock under static load and ultrahigh frequency alternating load. Numerical simulation and laboratory experimental methods were used in this paper to study the damage and fracture characteristics of rock under static loading and ultrasonic vibration. The variation laws of rock infrared temperature characteristics, porosity and compressive strength under different ultrasonic static loads were studied. The discrete element model of rock under ultrasonic vibration was established, and the numerical simulation was carried out by PFC2D software. We designed the ultrasonic rotary drilling device to verify the drilling effect. The process and mechanism of rock fragmentation under static load and ultrasonic vibration load were analyzed from the perspective of energy. Numerical simulation and experimental results showed that the combination of static load and ultrasonic vibration accelerates the failure speed of rock sample. The thermal infrared temperature characteristic test showed that the rock-breaking process under ultrasonic load and static load has three stages: stage I, elastic deformation and the temperature rises linearly; stage II, the development of microcrack and the temperature is further increased uniformly, and stage III, macrobreaking and rock chips falling off, and the temperature fluctuates sharply. There is a minimum threshold value for the promotion of static loading to break rock by ultrasonic vibration. Only when the static load is greater than 200 N, the crack propagation will occur in the rock sample. At this time, with the increase of static load, the crack propagation will further intensify, and the rock-breaking effect is more obvious. Under the same weight on bit (WOB), the penetration of rotary ultrasonic drilling can be increased by 13.93% ∼ 38.11% compared with conventional rotary drilling.

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Section: Introductionmentioning

confidence: 99%

Experimental and Simulation Study on Breaking Rock under Coupled Static Loading and Ultrasonic Vibration

Zhao

Zhang

et al. 2022

Shock and Vibration

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“…Keeping the impact frequency close to the rock natural frequency and selecting the appropriate static force are the key to improving the rock breaking efficiency [18]. Optimal impact frequency and static force in the test are 30 kHz and 200 N, respectively [19]. For rock thermal field evolution, Zhao et al [20] analyzed the evolution characteristics of the temperature field on the granite surface and established the critical criterion of rock damage based on the temperature variation laws.…”

Section: Introductionmentioning

confidence: 99%

Effect of Amplitude and Confining Pressure on Granite Failure under Ultrahigh Frequency (UHF) Impact Based on Radiation Temperature

Zhang

Dajun

2022

Geofluids

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Ultrahigh frequency impact technology has great potential to break hard rocks with lower energy consumption. Based on the infrared nondestructive testing technology, the effects of load (i.e., amplitude) and boundary (i.e., confining pressure) conditions on granite damage under ultrahigh frequency impact have been investigated to promote the application of this technology in rock engineering. Experimental results demonstrate that the evolution law of the maximum radiation temperature on granite surface reflects the granite damage state. Under ultrahigh impact, granite specimens are damaged effectively with the impact amplitude exceeding 32 μm, and the failure mode of the specimen is changed by the confining pressure. Depending on Griffith’s theory, the extension angle of the fatigue crack changes from 60 to 30 degrees with increasing confining pressure. And the transverse fracture occurs in the upper part of the specimen under ultrahigh frequency impact subjected to confining pressure. This research determines the amplitude threshold of the ultrahigh frequency impact load and verifies the effectiveness of ultrahigh frequency impact technology for granite failure subjected to confining pressure.

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“…Zhao et al [18] divided the granite rock sample body into three zones when subjected to ultrasonic vibration: the fracture zone, plastic deformation zone and elastic deformation zone. Zhou et al [19] investigated the effect of static loading on the natural frequency of the granite rock sample when subjected to ultrasonic vibration and found that the inherent frequency of rock increased logarithmically with the magnitude of static loading. The current research status indicates that the research on the application of ultrasonic technology in hard rock breaking is still in the first stage, the fatigue behaviour and crack evolution mechanism of rock under ultrasonic vibration are still unclear and, therefore, it is quite necessary to undertake research on these subjects.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of the fatigue behaviour and crack evolution mechanism of granite under ultra-high-frequency loading

et al. 2020

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Assisted ultrasonic vibration technology has received great interest in the past few years for petroleum and mining engineering related to hard rock breaking. Understanding the fatigue behaviour and damage characteristics of rock subject to ultra-high-frequency loading is vital for its application. In this research, we conducted ultrasonic vibration breaking rock experiments combined with an ultra-dynamic data receiver and strain gauges to monitor the development of strain in real time. The experimental results show that the strain curve is U-shaped, and it can be divided into three stages: the strain first decreases, then remains steady (with light fluctuations) and finally increases. The sample first underwent compressive deformation, and no rupture occurred. As the vibration continued, the compressive deformation decreased with the initiation and propagation of cracks, and fragmentation occurred. To elucidate the crack evolution mechanism of the granite specimens, numerical simulations were performed using particle flow code in two dimensions (PFC2D), and an improved fatigue damage model based on the flat-joint contact model was proposed. The numerical results indicate that this model can effectively reproduce the fatigue characteristics of hard brittle rocks under ultrasonic vibration. By analysing the stress and strain fields and cracking process, the crack evolution mechanism in the brittle hard rock under ultra-high-frequency loading is revealed. These experimental and numerical results are expected to improve the understanding of the fragmentation mechanism of rock under assisted ultrasonic vibration.

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Effect of Static Loading on Rock Fragmentation Efficiency Under Ultrasonic Vibration

Cited by 14 publications

References 28 publications

Experimental and Simulation Study on Breaking Rock under Coupled Static Loading and Ultrasonic Vibration

Experimental and Simulation Study on Breaking Rock under Coupled Static Loading and Ultrasonic Vibration

Effect of Amplitude and Confining Pressure on Granite Failure under Ultrahigh Frequency (UHF) Impact Based on Radiation Temperature

Experimental and numerical investigation of the fatigue behaviour and crack evolution mechanism of granite under ultra-high-frequency loading

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