Sensitivity Analysis of the Main Factors Controlling Floor Failure Depth and a Risk Evaluation of Floor Water Inrush for an Inclined Coal Seam

Liu, Weitao; Mu, Dianrui; Xie, Xiaochun; Li, Yang; Wang, Donghui

doi:10.1007/s10230-017-0497-6

Cited by 48 publications

(15 citation statements)

References 4 publications

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“…The mixture was then carefully transferred to a mould and compressed to yield a clear sheet, about 0.8 mm in thickness. 34 –38…”

Section: Methodsmentioning

confidence: 99%

Influence of synthetic conditions on the performance of melamine–phenol–formaldehyde resin microcapsules

Cheng

et al. 2018

High Performance Polymers

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Melamine (M), phenol (P) and formaldehyde (F) were used as raw materials to synthesize a melamine–phenol–formaldehyde resin (MPF) which was used as shell material to prepare a self-healing microcapsule with E-51 epoxy resin as the core, via in situ polymerization. Fourier transform infrared spectroscopy, environmental scanning electron microscopy and laser particle size analysis were used to characterize the surface morphology, structure and properties of the microcapsule. The influence of the reaction conditions on the properties of the microcapsule was investigated by orthogonal testing. The mass ratio between the MPF shell and the epoxy resin core was found to be 1.2:1.0, optimum pH for shell formation was found to be 3, the emulsification speed was 800 r/min, the acidification speed was 400 r/min and the acidification temperature was 60°C. Under these conditions, the prepared microcapsules are regular and spherical with a smooth, dense surface and uniform particle size with a normal distribution. The microcapsules remained well dispersed and did not aggregate. The orthogonal test revealed that the average particle size and yield of the microcapsules are mainly determined by the core/shell mass ratio, whereas the reaction temperature had a greater impact on the core content of the microcapsules. Although the best microcapsule samples showed poor anti-permeability in ethanol, they exhibited good thermal, isothermal and storage stabilities. This indicates that they may be stored at a constant temperature.

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“…The mixture was then carefully transferred to a mould and compressed to yield a clear sheet, about 0.8 mm in thickness. 34 –38…”

Section: Methodsmentioning

confidence: 99%

Influence of synthetic conditions on the performance of melamine–phenol–formaldehyde resin microcapsules

Cheng

et al. 2018

High Performance Polymers

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show abstract

“…Yin et al [15] analyzed the evolution law of underground water channels in the mining process by numerical simulation and found that the factors affecting the floor water inrush include the in situ stress, hydraulic pressure, working face width, mechanical properties of floor aquiclude, and breaking and swelling characteristics under hydraulic penetration. Liu et al [16] used the orthogonal experiment method to analyze the sensitivity of floor failure depth to various influencing factors and evaluated the risk of water inrush from the floor. Cheng et al [17] analyzed the influence of coal thickness, hydraulic pressure, thickness of the floor aquiclude, and other influencing factors on the risk of floor water inrush, comprehensively evaluated the influencing factors at different locations during the mining process, and believed that the open-off cut and the working face are the most likely locations for floor water inrush.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Analysis of the Failure Characteristics of Stope Floor Induced by Mining and Confined Aquifer

Lü

Wen-jun

Yin

et al. 2021

Shock and Vibration

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Mining above confined aquifer has become an important task for water inrush prevention in China. To study the failure characteristics of stope floor along the strike, a mechanical model under combined action of mining and confined aquifer was constructed, and the distribution of vertical stress, horizontal stress, and shear stress was obtained. Based on the Mohr–Coulomb criterion, the failure range of the floor is determined and verified by the in situ test. The results indicate the following. (1) Both vertical stress and horizontal stress in the stope floor take the junction of stress increasing area and stress decreasing area as the dividing line, forming two groups of “convex arches” at the solid coal side and the goaf side, respectively. (2) The vertical stress gradient in the solid coal side is significantly higher than that in the goaf side, while the horizontal stress gradient in the solid coal side is similar to that in the goaf side. The shear stress distribution is divided into three regions by the boundary between positive and negative shear stress, which makes the stope floor in this area to show compression shear or tension shear failure. (3) According to the in situ test, the maximum floor failure depth of 41503 working face is 11.38 m, which is quite close to the theoretical calculation result of 9.68 m. (4) Applying the mechanical model to five other coal mines with different mining conditions and stress states, the maximum absolute error between the measured and theoretical values of floor failure depth is 1.1 m, the average absolute error is 0.8 m, the maximum relative error is 8.2%, and the average relative error is 6.5%. The study provides a certain mechanical basis and reference for the floor failure mechanism induced by mining and confined aquifer.

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“…The probability of fracture and water inrush of the underlying coal seam increases with the increase of coal mining depth. The water inrush from the floor is directly related to the pressure of the mine [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Control of Water Inrush from Longwall Floor Aquifers Using a Division Paste Backfilling Method

Chang

Yao

et al. 2021

Geofluids

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Aiming at the problem of the safety mining problems of longwall paste filling working face under buildings on high confined water in the Daizhuang Coal Mine, the paste filling mining method was used. A series of theoretical analyses, numerical simulations, and field measurements were applied. The results showed that when the filling interval of the working face increases from 1.2 m to 3.6 m, no significant change is found in the depth of the perforated plastic zone of the floor strata. According to the types of water-conducting cracks in the floor strata of the working face 11607, the floor strata are divided into the floor intact area, the structure developed area, and the floor weak area. Based on that, the measures for preventing and controlling the floor failure in the paste filling working face are proposed. Furthermore, the failure depth of the floor of the test working face was detected by the on-site water injection method, and the results showed that the maximum failure depth of the floor of the test working face was about 3 m.

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Sensitivity Analysis of the Main Factors Controlling Floor Failure Depth and a Risk Evaluation of Floor Water Inrush for an Inclined Coal Seam

Cited by 48 publications

References 4 publications

Influence of synthetic conditions on the performance of melamine–phenol–formaldehyde resin microcapsules

Influence of synthetic conditions on the performance of melamine–phenol–formaldehyde resin microcapsules

Mechanical Analysis of the Failure Characteristics of Stope Floor Induced by Mining and Confined Aquifer

Control of Water Inrush from Longwall Floor Aquifers Using a Division Paste Backfilling Method

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