A novel anti-air-leakage method and an organic polymer material for improving methane drainage performance

Wang, Kai; Lou, Zhen; Wei, Guoying; Qin, Binbin; Wang, Liang

doi:10.1016/j.psep.2019.06.025

Cited by 30 publications

(10 citation statements)

References 23 publications

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“…Too many training modes will necessarily require a larger network structure, which reduces the learning efficiency and consumes considerable resources, and the learning of a few special data points may also be overwhelmed by a large amount of normal data, which makes it not prominent enough. Neural network prediction is not suitable for process prediction with stable processes but sudden change points [38][39][40][41][42][43] .…”

Section: Empirical Studymentioning

confidence: 99%

Research on residual GM optimization based on PEMEA-BP correction

Duan

Zhu

Wei

et al. 2020

Sci Rep

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With the advantages of small samples and high accuracy, Grey Model (GM) still has two major problems need to be addressed, high input data requirements and large margin of error. Hence, this paper proposes an algorithm based on Populational Entropy Based Mind Evolutionary Algorithm-Error Back Propagation Training Artificial Neural Algorithm to modify GM residual tail, which will not only keep the advantages of GM, but also expand its scope of use to various non-linear and even multidimensional objects. Meanwhile, it can avoid defects of other algorithms, such as slow convergence and easy to fall into the local minimum. In small samples data experiments, judging from SSE, MAE, MSE, MAPE, MRE and other indicators, this new algorithm has significant advantage over GM, BP algorithm and combined genetic algorithm in terms of simulation accuracy and convergence speed.

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Section: Empirical Studymentioning

confidence: 99%

Research on residual GM optimization based on PEMEA-BP correction

Duan

Zhu

Wei

et al. 2020

Sci Rep

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“…Scholars have carried out lots of research to enhance the sealing quality of borehole, and some methods were proposed to determine the sealing depth via in-situ tests [19,[30][31][32][33][34]. [20] analyzed the borehole drainage process by a compositional (CBM and air) model, and suggested that the air flow into the borehole through the excavationinduced fractures, which is the main cause for the air leakage of the borehole [19,20,35].…”

Section: Introductionmentioning

confidence: 99%

Improvement of Gas Drainage Efficiency via Optimization of Sealing Depth of Cross‐Measure Boreholes

Cheng

Chen

et al. 2021

Advances in Civil Engineering

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The sealing depth of a gas-drainage borehole is critically important as it directly affects the efficiency of the whole drainage system. In order to determine the shortest reasonable sealing depth, in this paper, a theoretical drainage model using different sealing depths was proposed. Based on theoretical analysis presented, two parts of the fractures system surrounding the drainage borehole were proposed, i.e. the fractures induced by roadway excavation and the fractures induced by borehole drilling. A series of geological in-situ tests and simulations research were conducted to determine the stress and fracture distributions in the surrounding rock of the borehole. The depths of crushing zones, plastic zones and stress concentration zones were determined as 5 m, 2 m and 12 m, respectively. Meanwhile, stress simulation shows that the depth of the stress concentration zone was 12 m from the roadway wall and the stress peak was located at the depth of 8 m, which can be verified by the results of drilling penetration velocity analysis. To determine the optimum sealing depth, gas drainage holes with different sealing depths were drilled in the field. The field results revealed that the crushing zones were the main area for air leakage, and the stress concentration induced by roadway excavation assisted in the reduction of air leakage. Therefore, the optimized sealing depth should both cover the plastic zone and the stress concentration zone. The research achievements can provide a quantitative method for the determination of optimum sealing depth in cross-measure drainage boreholes.

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“…The gas storage has reached 36.81 trillion cubic meters with the depth of <2000 m in China . In normal conditions, gas extraction is required before mining methane‐bearing coal seams to eliminate coal and gas outburst and use methane reasonably . As shown in Figure , gas predrainage is one of the effective methods to prevent coal and gas outbursts during coal roadway excavation.…”

Section: Introductionmentioning

confidence: 99%

“…2 In normal conditions, gas extraction is required before mining methane-bearing coal seams to eliminate coal and gas outburst and use methane reasonably. [3][4][5][6] As shown in Figure 1, gas predrainage is one of the effective methods to prevent coal and gas outbursts during coal roadway excavation. Cross-boreholes and in-seam boreholes are usually two types of boreholes layout for gas predrainage.…”

Section: Introductionmentioning

confidence: 99%

A new cross‐borehole hydraulic caving technique in the coal seam with a soft layer for preventing coal and gas outbursts during coal roadway excavation

Qin

Wei

Lou

et al. 2020

Energy Science & Engineering

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Predrainage of gas by cross‐boreholes is an important method to prevent coal and gas outbursts in the process of a coal roadway excavation. Limitations of technologies and poor effects of preventing coal and gas outbursts occur in the coal seam with a soft layer. In this study, a new hydraulic caving technology for cross‐boreholes has been proposed to solve this problem. A CT equipment was used to observe the development of coal fissures around cross‐boreholes in the coal seam with a soft layer. The plastic zone range and permeability distribution of ordinary hydraulic slotting technologies and the new hydraulic caving technology also were compared by numerical simulation. The field test of hydraulic caving was taken in the Xuehu Mine (China). The results show that the fracture development degree of soft coal is greater than that of hard coal at the same distance from cross‐boreholes. The fracture development degree in the plastic zone is greater than that in the elastic zone. The hydraulic caving technique can achieve the same effect as the ordinary hydraulic slotting with less workload. The mass of coal discharged from a cross‐borehole was 1.15 t/m and the average methane concentration of single drainage borehole increased by 1.09‐4.1 times, and the average methane extraction amount of single drainage borehole increased by 6.06 times. Elimination of coal and gas outburst had been completed after 110 days of extraction in the area of hydraulic caving, and Q and S values are lower than the critical value during roadway excavation. It is conclusion that hydraulic caving technique can effectively improve the permeability and rapidly eliminate coal and gas outburst in the coal seam with a soft layer.

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A novel anti-air-leakage method and an organic polymer material for improving methane drainage performance

Cited by 30 publications

References 23 publications

Research on residual GM optimization based on PEMEA-BP correction

Research on residual GM optimization based on PEMEA-BP correction

Improvement of Gas Drainage Efficiency via Optimization of Sealing Depth of Cross‐Measure Boreholes

A new cross‐borehole hydraulic caving technique in the coal seam with a soft layer for preventing coal and gas outbursts during coal roadway excavation

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