Investigation of the Heat-Treatment Effect on Rock Fragmentation Characteristics Using the Dynamic Ball Compression Test

Xu, Ying; Yao, Wei; Wang, Shuai; Xia, Kaiwen

doi:10.1007/s00603-019-02038-6

Cited by 36 publications

(15 citation statements)

References 60 publications

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“…Many previous studies have revealed that high temperatures could induce both transgranular and intergranular fractures in various granites (Nasseri et al 2009;Xu et al 2020). In most cases, visible cracks appear when the treatment temperature exceeds 600 °C (Xu et al 2020;Yin et al 2015) due to the α-β quartz phase transition that occurs at approximately 573 °C (Nasseri et al 2009). Thus, a temperature beyond 600 °C was used to induce thermal damage in the FG specimens.…”

Section: Determination Of Pretreatment Temperaturementioning

confidence: 99%

“…In this study, we investigated the water weakening effect of clay-free rocks with pores in the form of microcracks. Artificial porous rocks (APRs) were obtained by slow heating of Fangshan granite (FG), resulting in clay-free homogenous rock material with a high porosity (Wang et al 2020a;Xu et al 2020). APR specimens were first completely saturated and then subjected to an oven to obtain different saturations.…”

Section: Introductionmentioning

confidence: 99%

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Effect of water content on the mechanical properties of an artificial porous rock

Jiang

Chen

et al. 2021

Bull Eng Geol Environ

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Water content significantly affects the mechanical properties of porous rocks, for which both clay content and rock microstructure have been identified as main controlling factors. To study the influence of microstructure on the water effect on rock properties, artificial porous rock (APR) is made by heating Fangshan granite (FG). The mineral composition and microstructure of the thermally treated FG were determined, and 1000 °C was chosen as the treatment temperature to fabricate the APR. APR specimens with various water saturations (100%, 80%, 60%, 40%, 20%, and 0%) were prepared by drying fully saturated APR specimens. The quasi-static responses of the APR specimens during uniaxial and triaxial compression (with confining pressures of 5 MPa and 10 MPa) experiments were obtained. The results show that the uniaxial compressive strength (UCS) of the APR slightly increases with increasing water saturation from dry (0% saturation) to 60% saturation, and the cohesion shows a similar trend. However, the triaxial compressive strength decreases with increasing water saturation. The cohesion and internal frictional angle were obtained from the compression tests, and their dependence on the saturation was revealed, which can be explained by the interaction of the water and the rock microstructure. Keywords Heat treatment • Artificial porous rock (APR) • Water content • Water weakening mechanism • Saturation List of symbols APR Artificial porous rock CPL Cross polarized light CT Computed tomography FG Fangshan granite ISRM International Society for Rock Mechanics and Rock Engineering LVDT Linear variable differential transducer PPL Plane polarized light SEM Scanning electron microscopy UCS Uniaxial compressive strength n Porosity of rock specimen V v Pore volume of rock specimen (cm 3 ) V Bulk volume of rock specimen (cm 3 ) S r Degree of saturation (%) V w Volume of water (cm 3 ) f Ultimate shear stress (MPa) nor Normal stress (MPa) C Cohesion (MPa) Internal friction angle (°) F m Resisting stress of the meniscus effect w

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Section: Determination Of Pretreatment Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of water content on the mechanical properties of an artificial porous rock

Jiang

Chen

et al. 2021

Bull Eng Geol Environ

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“…[36][37][38] Numerous researchers have conducted laboratory tests to determine the effect of various types of damage on the weakening laws of rock mechanical properties. [39][40][41] However, due to the limitations of the testing techniques, the majority of conclusions are limited to the variation law of the macroscopic mechanical parameters of the damaged samples, with little attention given to the deterioration mechanism. For crystalline rocks, the mineral grains are significantly more resistant to damage than the grain boundary structure.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on the effect of intergranular contact bonding strength on the mechanical properties of granite using PFC3D‐GBM

Peng

Zhang

et al. 2023

Num Anal Meth Geomechanics

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In rock materials, the intergranular structure is more affected by various external conditions than the transgranular structure, and then dominates the macroscopic mechanical properties of rocks. In this paper, an innovative three‐dimensional grain‐based model based on Particle Flow Code (PFC3D‐GBM) for reproducing granite crystalline structures was developed. Based on this model, the Brazilian splitting test was conducted to investigate the effects of intergranular contact (IC) bonding strength on the mechanical properties and micro‐cracking behavior of the granite. Additionally, in this paper, the force chains and the orientation distribution of the force chains are shown in the form of three‐dimensional rose diagrams. The results are compared to the numerical results obtained by an initial particle‐based model to demonstrate the superiority of the proposed PFC3D‐GBM. The results indicate that the stress–strain curve of the sample in the Brazilian splitting test can be classified into four distinct stages: initial compaction, linear elasticity, damage, and splitting failure. ICs fracture at a higher rate than transgranular contacts (TCs) under static loading, as evidenced by experimental results of laboratory tests; during the entire loading process, all force chains uniformly distribute in all directions of a sample. As the external load increases, the number of total force chains decreases and the number of cracks increases. The main orientation of the high‐strength force chains is consistent with the external loading direction and is vertical with respect to the main orientation of the cracks. Furthermore, the number of high‐strength force chains increases with the level of external load. The sample's failure mechanism in the Brazilian splitting test is always a tensile failure, and this characteristic is unaffected by the modeling method or the IC bonding strength. Both the tensile strength and peak strain increase as the IC bonding strength increases. In this process, the number of total cracks in PFC3D‐GBM decreases, the proportion of transgranular cracks (Tcs) increases, and the proportion of intergranular cracks (Ics) decreases. The micro‐cracking behavior described above based on the PFC3D‐GBM can be explained more rationally. As the bonding strength of the IC increases, the particles involved in sample deformation are subjected to a greater stress concentration prior to the sample experiencing macro‐fracture, leading to an increase in the number of high‐strength force chains, which is the fundamental reason for the increase of the sample's tensile strength.

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“…Laboratory tests are an effective approach to observe the mechanical behavior of rock under loading or unloading conditions [37,38]. To observe the variation in the deformation, energy, or temperature during experiment tests on rocks, some advanced nondestructive measurement devices have been developed, such as infrared thermography, the use of high-speed cameras, and the digital image correlation method [39][40][41]. Among them, infrared thermography, which has recently been used to monitor surface temperature changes in rock experiments, was first developed for the military [42].…”

Section: Introductionmentioning

confidence: 99%

Research on the Mechanical Characteristics of Cyclic Loading and Unloading of Rock Based on Infrared Thermal Image Analysis

Zhou

Gao

et al. 2021

Mathematical Problems in Engineering

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In the operations of underground rock engineering, such as mining, the formation of goafs is often accompanied by unloading and energy effects. In this study, a cyclic loading and unloading stress test is carried out to analyze the strength characteristics of the loaded samples under different loading and unloading ranges as well as different numbers of cycles. The rock force is accompanied by substantial energy changes. To better fit the energy analysis under cyclic loading and unloading conditions, thermal infrared radiation characteristic analysis is performed during rock loading and unloading. An infrared radiation camera is adopted to detect the infrared characteristics of the rock force process after cyclic loading and unloading. Multiangle detection is implemented on the temperature, temperature field, and frequency histogram. The analysis shows that cyclic loading and unloading first strengthen and then weaken the rock. Moreover, the failure caused by the local stress concentration leads to a sharp increase in the temperature. There are significant temperature fluctuations before and after failure, and the temperature field after failure can be divided into three zones, namely, the normal temperature zone, heating zone, and mutational temperature zone, to comprehensively reflect that rock compression failure which is accompanied by the process of energy accumulation and release. On the basis of infrared energy analysis, the index of the energy release rate is introduced, and the loading and unloading analysis model is constructed. The research results reveal that rock failure is accompanied by the process of energy accumulation and release, which provides evidence for the analysis of the spatial stability of the rock mass under cyclic loading and unloading conditions and engineering excavation.

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Investigation of the Heat-Treatment Effect on Rock Fragmentation Characteristics Using the Dynamic Ball Compression Test

Cited by 36 publications

References 60 publications

Effect of water content on the mechanical properties of an artificial porous rock

Effect of water content on the mechanical properties of an artificial porous rock

Numerical investigation on the effect of intergranular contact bonding strength on the mechanical properties of granite using PFC3D‐GBM

Research on the Mechanical Characteristics of Cyclic Loading and Unloading of Rock Based on Infrared Thermal Image Analysis

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