Experimental study on dynamic mechanical responses of coal specimens under the combined dynamic-static loading

Pengfei, Lyu; Chen, Xuehua; Chen, Guangbo; Qiu, Lin

doi:10.1007/s12517-020-05985-5

Cited by 13 publications

(11 citation statements)

References 19 publications

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“…We found that the logarithmic form is the most consistent when we fit the curve of the experimental data. Some scholars have conducted similar studies using other rock materials [30,37]. An increase in static pre-stress weakens the strain rate effect on the SUCS.…”

Section: Test Results and Discussionmentioning

confidence: 97%

“…Recently, laboratory experiments were conducted to understand the mechanical properties of rock specimens in coal mines under superimposed static and dynamic loads, and the characteristics of the stress-strain curve, mechanical parameters and failure patterns have been presented [36]. For instance, Lyu et al [37] carried out uniaxial coupled statics and dynamics tests and acquired rock burst tendency of coal, the AE parameters, the failure mode and the fracture morphology. Zhao et al [38] conducted tests on coal specimens under different medium strain rates and proposed an empirical relationship between the peak strength and the strain rate; they also found that the evolution and distribution of stress and deformation were affected by the heterogeneity of the specimens.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties of Roof Rocks under Superimposed Static and Dynamic Loads with Medium Strain Rates in Coal Mines

et al. 2021

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Roof rocks in coal mines are subjected to the combination of in situ stresses and dynamic stresses induced by mining activities. Understanding the mechanical properties of roof rocks under static and dynamic loads at medium strain rates is of great significance to revealing the mechanism of rock bursts. In this study, we employ the digital image correlation (DIC) technique to investigate the energy concentration and dissipation behaviors, failure mode, and deformation characteristics of roof rocks under combined static and dynamic loads. Our results show that both the static pre-stress and dynamic loading rate have significant effects on the uniaxial compressive strength of rock specimens. From the energy principle, when the static pre-stress is the same, both elastic strain energy density and dissipated energy density increase with increasing dynamic loading rate. The hazard of rock bursts increases with decreasing static pre-stress and increasing dynamic loading rate. At higher dynamic loading rates, more cracks are generated, and the failure becomes more violent. The crack initiation, propagation and coalescence processes are identified, and the failure mode is closely related to the evolution of the global principal strain field of the rock specimens.

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Section: Test Results and Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Roof Rocks under Superimposed Static and Dynamic Loads with Medium Strain Rates in Coal Mines

et al. 2021

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“…where μ R is the friction factor of rock block; σ R is the normal stress on the contact surface of rock block, MPa; C R is the cohesion force of rock block, MPa; S is the interaction area between rock blocks, m 3 ; l is the side length of cubic rock block, m; and mn is the number of interacting rock blocks.…”

Section: Impact Energymentioning

confidence: 99%

“…Rockburst is one of the serious mine dynamic disasters [1][2][3][4][5]. According to the time of stress action, it can be divided into creep-type rockburst caused by static load stress and shock-type rockburst caused by mine earthquake action [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Vibration Energy Action on Dynamic Instability of Shock-Type Rockburst Carrier System

Pengfei

Xuekai

2020

Shock and Vibration

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In coal mining, the rockburst intensity triggered by the mine earthquake is often greater in the mining area, and the precursor information is more difficult to capture. In this paper, this kind of rockburst is called shock-type rockburst and studied as the research object. Based on the evolution process and the theoretical model of the carrier system, the energy criterion of the occurrence of shock-type rockburst was deduced based on the theories of mathematics and statistical physics. The results showed that the process of shock-type rockburst can go through four stages: inoculation stage, occurrence stage, development stage, and termination stage, and the secondary triggering phenomenon may occur in the occurrence stage. The theoretical model of the shock-type rockburst carrier system was constructed, and the key characteristic parameter of shock-type rockburst was put forward. Then, the energy of mine earthquake was quantitatively characterized in the form of kinetic energy of rock block. Through the combination of the two parameters, the energy criterion of shock-type rockburst was obtained as follows: once the energy of mine earthquake acting on the rockburst source area was 2%–9% of the static energy, shock-type rockburst can occur. Then, this criterion was verified by three typical cases. Finally, based on the distribution conditions of “red seam” overburden in the Yanzhou mining area of China, the secondary triggering principle of rockburst was expounded, that is, the secondary triggering principle of rockburst caused by the shear fracture and sliding settlement of “red seam” overburden. To sum up, a theoretical system for judging the instability of the shock-type rockburst carrier system was formed. This study provides a theoretical basis for earthquake prevention and disaster reduction in coal mining.

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“…[8][9][10]. Besides, shallow coals are gradually exhausted; the deep mining geological conditions are more complex; faults, folds, and other geological structures are concentrated, and the development situation of coal resources is extremely severe [11][12][13][14]. e study has shown that the occurrence of coal mine rockburst is closely related to geological structure and other factors; it is easy for rockburst to enter the concentrated burst, especially in the vicinity of faults [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

The Mechanical Criterion of Activation and Instability of Normal Fault Induced by the Movement of Key Stratum and Its Disaster‐Causing Mechanism of Rockburst in the Hanging Wall Mining

Pengfei

Jiabin

Wang

et al. 2021

Advances in Civil Engineering

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Coal mine rockburst is closely related to the complex geological structure. Understanding the criterion of the fault activation instability and the disaster-causing mechanism of rockburst under the influence of mining is the theoretical premise and important guarantee of safe and efficient coal mining. In this paper, based on the theory of key stratum, the mechanical model of fault slip instability in the normal fault during the hanging wall mining was established, and the instability criterion was derived. It is concluded that the fault slip instability of the hanging wall is mainly controlled by two factors: (1) the distance between coal seams and key stratum and (2) the distance between working face and fault. Moreover, these two factors have an inverse relation to the occurrence of rockburst. Subsequently, three conceptual models of rockburst induced by the fault stress transfer, stress concentration of coal pillars, and fault structural instability were proposed. Based on the rock mechanics theory, the rockburst carrier system model of “roof-coal seam-floor” near the fault was established. The mechanical essence of fault rockburst was obtained as follows: under the action of fault, the static load of fault coal pillar was increased and superimposed with the fault activation dynamic load, leading to high-strength rockburst disaster. Based on the occurrence mechanism of fault rockburst, the monitoring and prevention concept and technical measures were proposed in three aspects, including the monitoring and control of fault activation dynamic loads, the monitoring of high static load in fault coal pillar and stress release, and the strengthening roadway support. These prevention and control measures were verified in the panel 103down02 of the Baodian Coal Mine in engineering, and the effectiveness of these measures was proved.

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Experimental study on dynamic mechanical responses of coal specimens under the combined dynamic-static loading

Cited by 13 publications

References 19 publications

Mechanical Properties of Roof Rocks under Superimposed Static and Dynamic Loads with Medium Strain Rates in Coal Mines

Mechanical Properties of Roof Rocks under Superimposed Static and Dynamic Loads with Medium Strain Rates in Coal Mines

Mechanism of Vibration Energy Action on Dynamic Instability of Shock-Type Rockburst Carrier System

The Mechanical Criterion of Activation and Instability of Normal Fault Induced by the Movement of Key Stratum and Its Disaster‐Causing Mechanism of Rockburst in the Hanging Wall Mining

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