Design of Longwall Coal Pillar for the Prevention of Water Inrush from the Seam Floor with Through Fault

Li, Ang; Ji, Bing; Ma, Qiang; Liu, Chaoyang; Feng, Wang; Ma, Li; Mu, Pengfei; Mou, Lin; Yang, Yuxuan; Ding, Xuesong

doi:10.1155/2021/5536235

Cited by 7 publications

(4 citation statements)

References 18 publications

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“…2, to block the accumulation of water in the gob (Wang et al 2021;Chen et al 2022a;Galav et al 2022;He and Huang 2022;Fang et al 2023). The stability of these waterproof coal pillars has long been one of the critical research topics in coal mine development (Wang 2006;Hu et al 2019;Li et al 2021;He et al 2023).…”

Section: Introductionmentioning

confidence: 99%

Characteristics of waterproof failure and optimal width of narrow coal pillars under the coupled effects of mining, excavation and seepage

Chen,

Wang,

Bai

et al. 2024

Geomech. Geophys. Geo-energ. Geo-resour.

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The failure of waterproof coal pillars under the coupled effects of mining, excavation and water seepage is a significant factor contributing to sudden water inflow accidents in underground roadways. Investigating the instability characteristics and optimal width of waterproof coal pillars holds vital significance for water control and resource protection in mines. This study focus on the rational width of waterproof coal pillar at Dongzhuang Coal Mine in Shanxi Province. Using FLAC3D, a fluid–structure interaction numerical model of waterproof coal pillar was established, revealing the coupling characteristics of stress fields, plastic zones, and seepage zones within coal pillars under the influence of mining, excavation and water infiltration weakening. Furthermore, the stability characteristics of waterproof coal pillars with different widths were compared. The results are as follows: (1) Under the combined action of overlying strata pressure and water pressure from the gob, the coal mass on the water-inflow side of coal pillar is the first to fail. Additionally, with the infiltration of water, the elastic modulus, cohesion, and friction angle of the coal mass in the seepage zone decrease. (2) The lifecycle of waterproof coal pillar can be divided into three stages: working face mining, water infiltration from the gob, and roadway excavation. Based on this, the connectivity between plastic zones and seepage zones serves as the critical condition for the stability of waterproof coal pillar was proposed. (3) When the width of waterproof coal pillar is 3 m and 5 m, plastic zones become connected, forming a water-conducting channel. When the width of waterproof coal pillar is 7 m, 9 m, and 11 m, seepage zones and plastic zones are not connected, and the coal pillar exhibits load-bearing and water-barrier properties.

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Section: Introductionmentioning

confidence: 99%

Characteristics of waterproof failure and optimal width of narrow coal pillars under the coupled effects of mining, excavation and seepage

Chen,

Wang,

Bai

et al. 2024

Geomech. Geophys. Geo-energ. Geo-resour.

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“…Based on the hydraulic model of floor water inrush, Shi et al [20] put forward the calculation formula of the fault water-resisting coal pillar in the stope considering the influencing factors such as confined water pressure and coal seam dip angle. Li et al [21] determined the safe width of the water-resisting coal pillar in combination with the mechanical expression of the confined water pressure and the width of the water-resisting coal pillar under the limit equilibrium state. Wang et al [22] classified the structure of the water-resisting coal pillar into the plastic zone affected by rock pressure, the core zone with effective waterproof and the water pressure damage zone, and measured the physical shape distribution of the water-resisting coal pillar using ultrasonic detection technology.…”

Section: Introductionmentioning

confidence: 99%

Failure Characteristics of the Water-Resisting Coal Pillar under Stress-Seepage Coupling and Determination of Reasonable Coal Pillar Width

Liu

Xue

et al. 2023

Water

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Groundwater inrush hazard has always been a great threat to the construction of vertical shafts in coal mines. Generally, the failure of the water-resisting coal pillar under coupled stress-seepage conditions around the vertical shaft is the main reason for the generation of the water inrush channel. In order to understand the mechanical behaviors of the water-resisting coal pillar, the strength of typical coal affected by the size and water content was investigated, and the stress sensitivity of permeability was investigated by a stress-seepage coupling test. The stress field and deformation of the water-resisting coal pillar were investigated by numerical simulation, the stability of the water-resisting coal pillars with different widths was evaluated, and the reasonable width of the coal pillars under coupled stress-seepage condition was determined. Results show that the water content and coal pillar width have a great influence on the mechanical characteristics of coal samples. Under the conditions of lower water content and larger coal sample width, the coal sample presents higher strength, smaller axial deformation, smaller permeability and porosity, and weak sensitivity to stress. The simulation results show that the boundary of the main roadway at the end of the coal pillar is dominated by tensile stress, and fractures can significantly contribute to the destruction of coal pillars. With the increase in the width of the water-resisting coal pillar, the internal damage variable, maximum tensile stress, porosity, and average water flow velocity of the coal pillar decrease, which reduces the risk of water inrush and improves the safety of the water-resisting coal pillar. An evaluation model of the reasonable width of the water-resisting coal pillar under the stress-seepage coupling was proposed, and the model was verified by the shear slip law and experimental results. This study provides theoretical and experimental guidance for the risk management of groundwater inrush disaster during the construction of vertical shafts in coal mines.

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“…In article [26], the authors pointed out that geotechnology with backfill will minimize the development of cracks in the undermined salt mass and ensure the safety of waterproof rock strata, thus protecting the mine from emergency floods. Article [27] used finite difference software to analyze the laws of deformation and failure of the through-fault floor and fault activation under two different coal pillar width settings, and determined that the safety width of the waterproof coal pillar was 80 m.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Coal Floor Fault Activation Inducing Water Inrush Using Microseismic Monitoring—A Case Study in Zhaogu No. 1 Coal Mine of Henan Province, China

Xin

Jiang

Zhai³

et al. 2023

Sustainability

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Previously conducted studies have established that mining activities can activate faults, which will cause floor water inrush disasters and cause loss of personnel and property. In order to reduce the possibility of water inrush disasters in mining, it is particularly important to study the dynamic characteristics and rules of floor fault activation under the influence of mining. In this work, firstly, a microseismic monitoring system was established in the working face to analyze the changes of microseismic indexes before and after grouting. It was found that grouting can enhance the strength of a rock mass and play a role in sealing the water channel. Secondly, the quadratic kernel function of microseismic event energy was established. It was found that the accumulation degree of microseismic events and the region of high energy kernel density increased with the decrease of the distance between the working face and the left boundary of the “analysis region”. Combined with a microseismic event index and water inflow, the activation process of the floor fault was divided into five stages. Finally, the plastic failure region of surrounding rock under different excavation steps was analyzed by numerical simulation, and the characteristics of fault activation were further explained. A method of taking measures to prevent water inrush in the “sign stage of fault activation” was proposed.

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Design of Longwall Coal Pillar for the Prevention of Water Inrush from the Seam Floor with Through Fault

Cited by 7 publications

References 18 publications

Characteristics of waterproof failure and optimal width of narrow coal pillars under the coupled effects of mining, excavation and seepage

Characteristics of waterproof failure and optimal width of narrow coal pillars under the coupled effects of mining, excavation and seepage

Failure Characteristics of the Water-Resisting Coal Pillar under Stress-Seepage Coupling and Determination of Reasonable Coal Pillar Width

Analysis of Coal Floor Fault Activation Inducing Water Inrush Using Microseismic Monitoring—A Case Study in Zhaogu No. 1 Coal Mine of Henan Province, China

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