Crack propagation behavior in slit charge blasting under high static stress conditions

Yang, Renshu; Ding, Chuanxian; Li, Yongliang; Yang, Liyun; Zhao, Yong

doi:10.1016/j.ijrmms.2019.05.002

Cited by 81 publications

(35 citation statements)

References 20 publications

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“…Yang and Yang established a new type of digital laser dynamic caustics experimental system consisting of a digital laser system and a high-speed camera system [23]. On this basis, the caustic method is widely used to study the dynamic fracture process of materials [24][25][26].…”

Section: Eoretical Analysis Of the Caustic Curvementioning

confidence: 99%

Study on Crack Propagation of the Tunnel Model under Dynamic Loading

2021

Advances in Materials Science and Engineering

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Crack defects make it difficult to predict the dynamic fracture of tunnel specimens under an impact load. To study the impact of the velocity and crack location on a roadway under dynamic load, specimens with tunnel-type voids were made using polymethyl methacrylate. The split-Hopkinson bar was used as the loading method, and a digital laser dynamic caustics system was used to observe the fracture process of the specimens. The dynamic fracture process was evaluated by the crack propagation velocity, displacement, and dynamic stress intensity factor. To predict and verify the test results, ABAQUS was used to simulate the test process. It was found that the results of the simulated combinations of the crack propagation path and initial fracture toughness change law are consistent with the test results. The initial fracture toughness and the peak value of the crack propagation velocity increased with the increase of the impact velocity. The crack propagation law and trajectory were affected by the location of the prefabricated cracks.

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Section: Eoretical Analysis Of the Caustic Curvementioning

confidence: 99%

Study on Crack Propagation of the Tunnel Model under Dynamic Loading

2021

Advances in Materials Science and Engineering

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“…e static test is conducted by a material test system (MTS) hydraulic servo control machine, and the static uniaxial compressive strength (UCS) is 3.7 MPa with a loading rate of 0.6 mm/min. e pressure loading system is an independently designed loading device [19]. e specimen is placed under pressure via a jack to simulate the ground stress environment in which the rock would normally be located.…”

Section: Specimen Preparation and Con Ning Pressure Loadingmentioning

confidence: 99%

“…e existence of ground stress influences the stress field around the blasthole and the stress state of the rock mass. According to literature [19], under unidirectional stress, the radial normal stress and shear stress values at the circular hole are both zero; the circumferential normal stress can be expressed as follows:…”

Section: Effect Of In Situ Stress On Crack Propagationmentioning

confidence: 99%

In Situ Stress Effects on Smooth Blasting: Model Test and Analysis

Yang

Fang

Yang

et al. 2020

Shock and Vibration

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Most of the roadway excavation is completed by the drilling and blasting method. With the increase of buried depth, the existence of ground stress will generate a significant impact on the rock blasting, especially on the smooth blasting. In this study, self-made homogeneous similar materials and digital image correlation methods were used to determine influence of ground stress on the smooth blasting under uniform explosive charge parameters and various in situ stress conditions. The results show that the crack outline after blasting changes from zigzag to straight in shape, and multifractal calculation results of the rupture section between blastholes show that the fracture surface becomes flatter as ground stress increases, which is conducive to roadway formation. The strain and equivalent strain rate obviously decrease as the distance between the blasthole and measuring points increases. The same trend occurs as the confining pressure goes up. Meanwhile, a postexplosion acoustic wave test indicates that confining pressure inhibits damage of the retained rock, which is consistent with strain and equivalent strain rate results. Finally, we discussed the crack propagation mechanism of rock in smooth blasting.

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“…They discovered that the deep water pressure exerts great adverse effects on the tunneling process, as well as on the support of the tunnel wall. Yang et al [14] studied the blast-induced crack propagation behavior of slotted charge blasting under initial static compressive stress using a dynamic caustic experiment and reported that the stress distribution around the blasthole and the blast-induced gas influences the entire propagation process. With respect to mining a region with high rock blasting risk, Konicek et al [15] expounded the application of pressure blasting to rock masses and stated that the high ground stress had a certain influence on the blasting effect.…”

Section: State Of the Artmentioning

confidence: 99%

Experimental Study on Notched Directional Blasting in Tensile Stress Field

Xie¹,

Huang²,

Zhang³

et al. 2020

JESTR

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Notched blasting has been extensively applied as a traditional directional blasting method. At present, the measurement of notched blasting effect and rock fragmentation is mainly decided by the propagation behavior of blast-induced cracks. However, the influence of initial tensile stress field on such behavior is rarely considered in existing engineering blasting process, resulting in the non-remarkable directional fracture effect of tensile rock mass. To reveal the propagation behavior of the propagation behavior of blast-induced cracks in the initial tensile stress field, as well as the fracture failure mechanism, the stress distribution state and propagation mechanism of the blast-induced cracks near the notched hole under the combined action of initial tensile stress and blasting stress were determined on the basis of the theory of elastic and fracture mechanics. The combined dynamic-static loading device and digital laser caustic experimental system were used to conduct the planar model failure experiment under the joint action of the initial tensile and blasting stress. The influence laws of the initial tensile stress and notch angle on the propagation length and velocity of the blastinduced main cracks, as well as the stress intensity factor at the crack tip, were also investigated through the experiment. The results showed that, (1) In the initial tensile stress field, as circumferential tensile stress was generated at the blasthole wall by initial tensile stress, the blast-induced main crack could be more easily propagate in the direction perpendicular to the initial tensile stress. (2) When the angle between the notch and the initial tensile stress was 45°, the initial tensile stress enlarged the propagation length of the main crack, and the propagation mode transitioned from Mode I to I-II mixed mode. In the meantime, the main crack deflected perpendicular to the initial tensile stress. (3) When the notch was parallel to the initial tensile stress, the main crack demonstrated a linear propagation along the direction of initial tensile stress. The initial tensile stress promoted the generation of the secondary cracks in the two sides of the blasthole and shortened the propagation length of the main crack, thereby reducing the stress intensity factor of the main crack. Results can serve as a reference for directional blasting in the initial static tensile stress field.

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Crack propagation behavior in slit charge blasting under high static stress conditions

Cited by 81 publications

References 20 publications

Study on Crack Propagation of the Tunnel Model under Dynamic Loading

Study on Crack Propagation of the Tunnel Model under Dynamic Loading

In Situ Stress Effects on Smooth Blasting: Model Test and Analysis

Experimental Study on Notched Directional Blasting in Tensile Stress Field

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