Micro-textural effects on crack initiation and crack propagation of andesitic rocks

Ündül, Ömer; Amann, Florian; Aysal, Namık; Plötze, Michael

doi:10.1016/j.enggeo.2015.04.024

Cited by 55 publications

(9 citation statements)

References 37 publications

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“…Gao et al presented that the macroscopic failure of rock is a gradual process, which is caused by the germination, expansion, evolution, and coalescence of its internal microcracks [24]. Microcracking is highly dependent on the mineralogy, fabric, and microstructure of a given rock type [25][26][27]. Granite contains a variety of rock-forming minerals and contains many original defects.…”

Section: Resultsmentioning

confidence: 99%

“…Microcracking is highly dependent on the mineralogy, fabric, and microstructure of a given rock type [25][26][27]. erefore microtextural variations are essential for understanding variation in strength and failure behavior of rocks [26]. e extension path of rock internal cracks under low-frequency loads has been reported by several researchers.…”

Section: Macroscopic Destruction Of Granitementioning

confidence: 99%

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Microcrack Growth Properties of Granite under Ultrasonic High‐Frequency Excitation

Zhao

Zhang

Wang

2019

Advances in Civil Engineering

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The failure of most rock materials is essentially a process of crack initiation and propagation. It is of great significance to study the microcrack growth characteristics of granite under ultrasonic high-frequency excitation for understanding the failure mechanism of rock under ultrasonic vibration. In this paper, the experimental and numerical simulation methods are used to study the propagation characteristics of rock cracks under ultrasonic vibration. Scanning electron microscopy (SEM) was used to observe the growth of microcracks in granite samples after ultrasonic vibration for 0 min, 2 min, and 4 min. A discrete element software PFC2D was used to simulate and solve the cracking mechanism of rock cracks under ultrasonic vibration. Also, it is found that the action of ultrasonic vibration can effectively promote the development of microcracks in the granite samples. The main three cracks causing the failure of quartz under the ultrasonic high frequency are intragranular cracks, transgranular cracks, and grain boundary cracks. The breakage of transgranular cracks usually contributes a shell-like fracture, that is, a regular curved surface with a concentric circular pattern appears on the fracture surface, which is a typical quartz brittle fracture mode. In addition, the feldspar grain failure is mainly caused by intragranular crack and transgranular crack. Microcracks are wavy expansion in feldspar grain. Mica failure is mainly caused by grain boundary crack, and the effect of lamellar cleavage on the failure of mica is significant. Moreover, it is also found that the mechanism of microcrack propagation is tensile failure. The failure of feldspar grains is mainly contributed to the failure of granite.

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Section: Resultsmentioning

confidence: 99%

Section: Macroscopic Destruction Of Granitementioning

confidence: 99%

Microcrack Growth Properties of Granite under Ultrasonic High‐Frequency Excitation

Zhao

Zhang

Wang

2019

Advances in Civil Engineering

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“…Microstructure characteristics are related to the grain size, grain shape, and distribution in the matrix, porosity, interlocking, mineralogical composition, quartz content, and etc. So far many laboratory studies have been done for finding the relationship between microstructures of rock and macro scale features (Olsson, 1974;Eberhardt et al, 1999;Palchik & Hatzor, 2004;Tandon & Gupta, 2013;Amann et al, 2014;Ghazvinian et al, 2015;Ündül et al, 2015;Ündül, 2016;Farrokhrouz & Asef, 2017;Festa et al, 2018;Garia et al, 2019;Aladejare, 2020;Hemmati et al, 2020), as well as numerical simulation by discrete element method (Lan et al, 2010;Nicksiar & Martin, 2014;Tan et al, 2016), however, many of the results are not conclusive.…”

Section: Introductionmentioning

confidence: 99%

Physical Parameters, Tensile and Compressive Strength of Dolomite Rock Samples: Influence of Grain Size

Lakirouhani

Asemi

Zohdi

et al. 2020

Journal of Civil Engineering and Management

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The purpose of this paper is to investigate the strength, physical and engineering index parameters of selected dolomitic rocks with emphasis on grain size. For this purpose, three groups of dolomite from north western Iran, with the same mineral composition but different grain size, were selected; fine grain, medium grain and coarse grain. Three sets of laboratory experiments are performed on 32 samples: first; petrography tests for determining mineral composition and their percentage, and microstructure of rock containing grain size and grain size distribution, second; experiments to determine the physical properties of the rocks included density, compressional and shear wave velocity, and the third category of experiments included uniaxial compressive strength test, Brazilian tensile strength and point load strength. According to the results; there are significant positive correlation between grain size and uniaxial compressive strength (r = 0.89), point load strength (r = 0.58), Brazilian strength (r = 0.69), and average Young’s modulus (r = 0.64). Also, with increasing grain size, density decreases (r = –0.77). There is strong correlation between compressional wave velocity and shear velocity (r = 0.88). There are also a strong correlation among the uniaxial compressive strength, Brazilian tensile strength and point load strength.

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“…From the observations in the laboratory tests, it is known that the crack initiates usually in the matrix (Amann et al [1]; Ündül et al [2]). The crack propagation are much dependant on the stress magnitude, micro-damage localization and mineralogical features such as type, percentage, and microstructure (Amann et al [1]; Ündül et al [2]; Lin and Labuz [3]), and eventually change the strength of rocks.…”

Section: Introductionmentioning

confidence: 99%

“…The crack propagation are much dependant on the stress magnitude, micro-damage localization and mineralogical features such as type, percentage, and microstructure (Amann et al [1]; Ündül et al [2]; Lin and Labuz [3]), and eventually change the strength of rocks. The orientation, velocity, and length of crack propagation are much related to the crack types (Rigopoulos et al [4]).…”

Section: Introductionmentioning

confidence: 99%

Variations in Crack Features of Granite Specimen During Laboratory Uniaxial Compression Test Using Image Processing

Wang¹,

Xu²,

Cao³

2018

dtetr

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The granite is a heterogeneous rock consisting of various microscopic compositions (i.e., quartz, feldspar, biotite, etc). Changes in the digital features of these compositions are important in understanding the deformation and failure mechanisms of the rock. The video images photographed during the uni-axial compression test were used to investigate the digital changes of the cracks in the rock. The original images were first transferred into the gray and binary ones using the digital image processing. The positions of cracks were extracted using the grayscale threshold segmentation and traditional visual identification. The changes in the digital features of the cracks were furthermore explored in various stages during the specimen failure. It shows that the failure process of the granite specimen may be divided into three stages, or, stable, speeded, and complete ones; at the stable stage, the first crack initiates and propagates gradually with the great changes in the crack features; at the speeded stage, two of new cracks generate and all of cracks propagate much quickly; at the complete failure stage, all of the cracks changes gradually again until the rock approached to failure. The results presented herein may be referable in investigating the failure mechanism of the rock material.

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Micro-textural effects on crack initiation and crack propagation of andesitic rocks

Cited by 55 publications

References 37 publications

Microcrack Growth Properties of Granite under Ultrasonic High‐Frequency Excitation

Microcrack Growth Properties of Granite under Ultrasonic High‐Frequency Excitation

Physical Parameters, Tensile and Compressive Strength of Dolomite Rock Samples: Influence of Grain Size

Variations in Crack Features of Granite Specimen During Laboratory Uniaxial Compression Test Using Image Processing

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