Safety classification and application of coal-rock gas compound dynamic disaster in coal mine

Deep coal mining is seriously affected by a combined dynamic disaster of rock burst and coal and gas outburst, but the influence mechanism of gas on this combined dynamic disaster is still not very clear, which is significantly different from the single type disasters. In this study, to explore the effect of gas on the coal-rock burst, a novel gas-solid coupling loading apparatus is designed to realize gas adsorption of coal sample with burst proneness and provide uniaxial loading environment under different gas pressure. A series of uniaxial compression tests of gas-containing coal with different gas pressure is carried out, and the energy dissipation process is monitored by an acoustic emission (AE) system. Results show that the macroscopic volume strain of the coal sample increases as gas adsorption and gas pressure increase under constant uniaxial loading pressure. Gas has the ability to expand the pores and natural fractures in coal sample by mechanical and physicochemical effects, which leads to a degradation in microstructure integrity of coal sample. With the increase of gas pressure, both the macrouniaxial compression strength (UCS) and elastic modulus show a downward trend; the UCS and elastic modulus of coal samples with 2 MPa gas pressure reduce by 58.78% and 48.82%, respectively, compared to those of the original coal samples. The main reason is that gas changes the pore-fissure structure and the mesoscopic stress environment inside the coal sample. Owing to the gas, the accumulated elastic energy of the gas-containing coal samples before failure reduces significantly, whereas the energy dissipated during loading increases, and the energy release process in the postpeak stage is smoother, indicating the participation of gas weakens the burst proneness of the coal sample. This study is of important scientific value for revealing the mechanism of combined dynamic disaster and the critical occurrence conditions of coal-rock burst and coal and gas outburst.

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Analysis on Production of Coal Bed Methane Considering the Change in Permeability of Coal Rock

The Open Petroleum Engineering Journal ◽

10.2174/1874834101609010289 ◽

2016 ◽

Vol 9 (1) ◽

pp. 289-298 ◽

Cited By ~ 2

Author(s):

Zhu Likai ◽

Ji Youjun ◽

Yang Tianhong ◽

Li Xiaoyu

Keyword(s):

Coal Mine ◽

Confining Pressure ◽

Gas Production ◽

Coal Bed ◽

Coal Bed Methane ◽

Methane Extraction ◽

Coal Rock ◽

Cbm Production ◽

Stable Yield ◽

Set Up

Based on the mechanism of migration of the coal bed methane (CBM), and taking into account the deformation of the coal rock during the process of CBM production was also taken into account, a coupled mathematical model considering the interaction of solid and fluid for methane extraction was built. The coal gas extraction of JINcheng coal mine was taken as an example, some typical coal sample was chosen to test the permeability under different confining pressure. The curve for permeability of coal rock versus effective stress under different confining pressure was obtained, a numerical model considering the variation of permeability for methane extraction was set up. The influence of deformation of coal rock on the gas production was simulated and analyzed. The simulation results indicate that the productivity curve considering deformation of rock is closer to the actual production data, at the initial stage of production, the gas rate is less than the case without considering deformation of rock, but the time of stable yield will last longer, and this matches the actual methane extraction, therefore, we recommend that the deformation of coal seam should be considered during the prediction of methane production for JINcheng coal mine.

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The Pressure Relief Control Technology of the Defects Method on Dynamic Pressure Area in Zhaogezhuang Coal Mine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.152-154.1097 ◽

2012 ◽

Vol 152-154 ◽

pp. 1097-1101

Author(s):

Zhong Dong Yang

Keyword(s):

Coal Mine ◽

Simulation Analysis ◽

Dynamic Pressure ◽

High Stress ◽

Good Effect ◽

Pressure Relief ◽

Working Face ◽

Pressure Area ◽

Stress Zone ◽

Coal Rock

Because of deep mining and the serious dynamic pressure appearance in Zhaogezhuang coal mine, this paper has statistical and analyzed phenomena of dynamic pressure appearance, and proposed the engineering defects method to relief the pressure for high stress zone of working face and roadway according to the actual situation, which can transfer the stress distribution of coal rock and release impact energy. Based on the numerical simulation analysis of pressure relief on cavity defects, it has analyzed the feasibility of pressure relief using engineering defect, acquired good effect of pressure relief and achieved the safety of coal mining in the 2337E working face.

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Simulation and Parameters Analysis of Fault Geological Structure for Detection in the Excavation Face

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.448-453.3742 ◽

2013 ◽

Vol 448-453 ◽

pp. 3742-3746

Author(s):

Wei Jie Zhang ◽

Ming Rui Hao ◽

Zhi Min Liu ◽

Xi Gao Liu ◽

Miao Wu

Keyword(s):

Coal Mine ◽

Apparent Resistivity ◽

Induce Polarization ◽

Geological Structure ◽

Electrical Parameters ◽

Detection Model ◽

Detection Technology ◽

Mine Roadway ◽

Coal Rock ◽

Parameters Analysis

In order to study on the advanced detection technology and the sensitivity of the Fault geological structure based on induce polarization (IP) method, and analyze the hazards of the Fault geological structure in front of the excavation face of coal mine roadway. This paper establishes a simplified physical model of the structure and converts the model into an equivalent circuit for convenient study and then constructs an IP model of the Fault geological structure. The IP model is connected with the simulation detection model of geological abnormal mass to obtain the changed curves of the apparent resistivity and the apparent frequency under the IP mode. The curves obtained show that simulation detection results agree with the electrical parameters specified by the IP model. Therefore the basic idea of the electric method detection is verified, which will provide a feasible presupposition for the development of the coal (rock) IP effect based on the advanced detection instruments with the electric method.

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Study on the Technology of Enhancing Permeability by Millisecond Blasting in Sanyuan Coal Mine

Mathematical Problems in Engineering ◽

10.1155/2021/8247382 ◽

2021 ◽

Vol 2021 ◽

pp. 1-12

Author(s):

Dan Zhao ◽

Mingyu Wang ◽

Xinhao Gao

Keyword(s):

Coal Seam ◽

Coal Mine ◽

Simulation Software ◽

Low Permeability ◽

Time Interval ◽

Rock Blasting ◽

Deep Hole ◽

Coal Seams ◽

Coal Rock ◽

Gas Coal

To reduce gas disasters in low permeability and high-gas coal seams and improve gas predrainage efficiency, conventional deep-hole presplitting blasting permeability increasing technology was refined and perfected. The numerical calculation model of presplitting blasting was established by using ANSYS/LS-DYNA numerical simulation software. The damage degree of coal and rock blasting was quantitatively evaluated by using the value range of the damage variable D. According to the actual field test parameters of coal seam #3 in the Sanyuan coal mine, Dlim = 0.81–1.0 was the coal rock crushing area, Dlim = 0.19–0.81 was the coal rock crack area, and Dlim = 0–0.19 was the coal rock disturbance area. By comparing and analysing the damage distribution nephogram of coal and rock mass under the influence of different millisecond blasting time interval and the blasting effect of simulation model, the optimal layout parameters of multilayer through cracks were obtained theoretically. And, the determined parameters were tested on the working face of the 1312 transportation roadway in coal seam #3 of the Sanyuan coal mine. The permeability effect was compared and analysed through the analysis of the gas concentration, gas purity, and mixing volume before and after the implementation of deep-hole presplitting blasting antireflection technology, as well as the change of gas pressure, attenuation coefficient, permeability coefficient, and other parameters between blasting coal seams. The positive role of millisecond blasting in reducing pressure and increasing permeability in low permeability and high-gas coal seam were determined.

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The Properties of a Coal Body and Prediction of Compound Coal-Rock Dynamic Disasters

Shock and Vibration ◽

10.1155/2020/8830371 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Guowei Dong ◽

Xuanming Liang ◽

Zhen Wang

Keyword(s):

Prediction Method ◽

Gas Pressure ◽

Mathematical Treatment ◽

Predictive Index ◽

Crustal Stress ◽

Gas Desorption ◽

Analysis Laboratory ◽

Coal Rock ◽

Dynamic Disaster ◽

Increasing Temperature

Since the precise identification and prediction and early warning of compound coal-rock dynamic disaster remain difficult, a new coal characterisation and prediction method for compound coal-rock dynamic disasters was described based on theoretical analysis, laboratory experiment, field sampling, mathematical treatment, and industrial testing. The results implied that the physicomechanical properties of coal in a compound coal-rock dynamic disaster are between those pertinent to a typical rock burst and a coal-gas outburst, i.e., with high crustal stress surrounding pressure, high gas pressure, low permeability, bump proneness, and outburst risk. The predicted drilling data indicate moderate gas desorption indices. The gas desorption velocity and permeability of compound coal-rock dynamic disaster coal decrease with the increase in crustal stress, while increase and decrease with the increase in gas pressure, respectively, at the same time, and they change little with increasing temperature. Gas extraction leads to the increase in coal mass brittleness and bump proneness. Based on the unique physical-mechanical properties of compound coal-rock dynamic disaster coal, a reasonably sensitive predictive index and critical value for Donglin Coal Mine were determined.

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Study on Safety Control of Composite Roof in Deep Roadway Based on Energy Balance Theory

Sustainability ◽

10.3390/su11133688 ◽

2019 ◽

Vol 11 (13) ◽

pp. 3688 ◽

Cited By ~ 3

Author(s):

Zhengzheng Xie ◽

Nong Zhang ◽

Yuxin Yuan ◽

Guang Xu ◽

Qun Wei

Keyword(s):

Energy Balance ◽

Energy Release ◽

Coal Mine ◽

Balance Theory ◽

Dissipation Energy ◽

Safety Control ◽

Deformation Control ◽

Low Dissipation ◽

Coal Rock ◽

Safety And Stability

Improving the safety and stability of composite roof in deep roadway is the strong guarantee for safe mining and sustainable development of coal mines. With three roadways of different composite roofs in Hulusu Coal Mine and Menkeqing Coal Mine as the research background, this paper explores the mechanical properties and energy dissipation law of coal-rock structures with different height ratios from the perspective of energy release and dissipation through lab experiments. The results indicate that the key to the stability of coal-rock structures lies in maintaining relatively low dissipation energy. Based on experimental results and the energy balance theory, two support principles were put forward and applied to experimental roadways. The field monitoring results show that the anchoring force on different composite roof displays different characteristics, proving that the work done by the support can adjust timely to the energy release and conversion so as to improve the safety and stability of roadways with different composite roofs. This study provides a reference for the deformation control in deep roadways with composite roofs under similar conditions.

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Rock Bolting Numerical Simulation Research and Application of the Face Breakthough

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.105-107.2239 ◽

2011 ◽

Vol 105-107 ◽

pp. 2239-2243

Author(s):

You Lin Xu ◽

Hui Zhang ◽

Wei Zheng

Keyword(s):

Numerical Simulation ◽

Coal Mine ◽

Rock Strength ◽

Test Methods ◽

Strength Test ◽

Simulation Research ◽

Rock Bolting ◽

Mine Roadway ◽

The Face ◽

Coal Rock

This paper analyzes the importance of rock bolting in coal mining, and the difficult of using rock bolting in breakthough with the affect of mining, adopt hydraulic fracturing and coal-rock mass strength test methods to test the seam stress and rock strength. Make the numerical simulation of break though bolting solutions in coal mine roadway by using FLAC3D software, simulate the different distributions of pre-stressed in coal-rock with three situations, the same raw distance but different space, the same space but different raw distance, impose different preload on the roof anchor in the rock bolting of mine roadway breakthough. Then determine a reasonable bolting solution of coal mine roadway according to the case of prestressed in coal-rock.

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