Study on Dynamic Compressive Mechanical Properties and Failure Modes of Heat-Treated Granite

Wang, Zhiliang; Hao, Shiyun

doi:10.1590/1679-78253342

Cited by 16 publications

(7 citation statements)

References 20 publications

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“…Nevertheless, due to the limitation of test conditions, the majority of scholars adopted the test method that the sample was heated before the implementation of the SHPB test, in the early research [5,6]. Macroscopically, when the temperature was fixed, the dynamic peak strain and strength of rock increased with the increase of the strain rate, which was basically similar to dynamic response characteristics of rocks at room temperature [7]. In contrast, under the condition of fixed strain rate, with the increase of temperature, the dynamic compressive strength of rock approximately firstly increased and then decreased.…”

Section: Introductionmentioning

confidence: 95%

Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

Zhang

Lin

et al. 2021

Geofluids

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The research on dynamic mechanical properties of rocks under high temperature is the basis for safe and efficient implementation of deep coal mining and underground coal gasification engineering. In this paper, the split Hopkinson bar (SHPB) with real-time high-temperature function was adopted to systematically study dynamic mechanical properties of sandstones. The research showed that under the condition of a fixed temperature, with the increase of strain rate, the dynamic compressive strength and dynamic peak strain of sandstone increased gradually, and the variation of dynamic elastic modulus with strain rate was not obvious. With the increase of temperature, the dynamic compressive strength of sandstone increased first and then decreased, the dynamic peak strain increased gradually, and the dynamic elastic modulus decreased overall. The variation law of macroscopic failure mode and energy dissipation density with temperature was revealed, and the change mechanism was explained considering the influence of high temperature on the internal structure of sandstone. Based on the principle of component combination and the theory of micro-element strength distribution, the dynamic statistical damage constitutive model was established, and its parameters had certain physical significance. Compared with the experimental results, the established model can well describe the dynamic stress-strain relationship of sandstone under real-time high temperature.

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Section: Introductionmentioning

confidence: 95%

Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

Zhang

Lin

et al. 2021

Geofluids

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“…Before the experiment, all the granite specimens were processed into standard rock specimens with a diameter of 50 mm and a height of 25 mm. Moreover, the length-diameter ratio was 0.5 to satisfy the hypothesis of stress uniformity, 22,[42][43][44] as shown in Figure 1. An acoustic test was performed to ensure that all samples' acoustic velocity difference was slight, and select pieces with similar mechanical properties while minimizing the error caused by rock heterogeneity.…”

Section: Specimen Preparationmentioning

confidence: 99%

Experimental study of the influence of temperature and cooling method on dynamic mechanical properties and damage of granite

Wang

Zha

et al. 2022

Energy Science & Engineering

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The change in mechanical properties of high‐temperature rock after cooling treatments is getting increasing attention. However, only a few studies have been conducted on the dynamic characteristic parameters. Therefore, this study aims to perform a dynamic damage analysis of high‐temperature rocks subjected to different thermal shocks. Accordingly, the specimens were grouped and heated to 200°C, 400°C, 600°C, and 800°C, and they were cooled by natural, water, and liquid nitrogen cooling. Ultrasonic detector tests, the split Hopkinson pressure bar experiments, and scanning electron microscope tests of the high‐temperature granite specimens were conducted using different cooling methods. Subsequently, the change rules of dynamic stress–strain curves and properties were calculated, and the morphology and micromorphology of fragments were compared. Based on the outcomes, the thermal shock damage and impact damage evolution were evaluated and quantified. The findings revealed that when the treatment temperature increases, the dynamic peak stress and elastic modulus decrease, while the peak strain increases, and the effect of rapid cooling was more significant in the influence of rock dynamic characteristics. Moreover, when the damage factor is more than 0.51, the change of dynamic stress‐strain is accelerated, leading to the instability of the structure under the impact load. The research results are expected to provide an adequate theoretical basis for the development and utilization of geothermal resources and underground engineering applications.

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“…The difference among the elastic moduli of the 20°C, 200°C, and 400°C samples is not significant at the 1 st impact, but the elastic modulus of the 600°C treated sample is much lower than those of the other three. This indicates that the deformation resistance of the 600°C treated sample reduces greatly [Wang and Hao (2017)]. For the samples after 20°C, 200°C, and 400°C treatments, the elastic moduli increase at the initial impacts due to compaction, and then decrease because of the damage-softening effect.…”

Section: Variation Of Peak Stress Peak Strain and Elastic Modulusmentioning

confidence: 99%

Mechanical Response and Energy Dissipation Analysis of Heat-Treated Granite Under Repeated Impact Loading

Wang¹,

Tian²,

Wang³

et al. 2019

Computers, Materials &Amp; Continua

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The mechanical behaviors and energy dissipation characteristics of heat-treated granite were investigated under repeated impact loading. The granite samples were firstly heat-treated at the temperature of 20°C, 200°C, 400°C, and 600°C, respectively. The thermal damage characteristics of these samples were then observed and measured before impact tests. Dynamic impact compression tests finally were carried out using a modified split-Hopkinson pressure bar under three impact velocities of 12 m/s, 15 m/s, and 18 m/s. These test results show that the mineral composition and the main oxides of the granite do not change with these treatment temperatures. The number of microcracks and microvoids decreases in the sample after 200°C treatment. The mechanical properties of a sample after 600°C treatment were rapidly deteriorated under the same impact velocity. The average of peak stress is much smaller than those after 20°C, 200°C and 400°C treatments. The heat-treated samples have an energy threshold each. When the dissipated energy of a sample under a single impact is less than this threshold, the repeated impacts hardly lead to further damage accumulation even if its total breakage energy dissipation (BED) density is large. Under the same number of repeated impacts, the cumulative BED density of a sample after 600°C treatment is the largest and its damage evolves most quickly. The total BED density of the sample after 200°C treatment is the highest, which implies that this sample has better resistance to repeated impact, thus having less crack initiation and growth.

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Study on Dynamic Compressive Mechanical Properties and Failure Modes of Heat-Treated Granite

Cited by 16 publications

References 20 publications

Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

Study on Dynamic Mechanical Properties and Failure Mechanism of Sandstones under Real-Time High Temperature

Experimental study of the influence of temperature and cooling method on dynamic mechanical properties and damage of granite

Mechanical Response and Energy Dissipation Analysis of Heat-Treated Granite Under Repeated Impact Loading

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