Theoretical and numerical investigations on mining-induced fault activation and groundwater outburst of coal seam floor

Song, Wencheng; Liang, Zhongmin

doi:10.1007/s10064-021-02245-y

Cited by 31 publications

(11 citation statements)

References 42 publications

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“…In order to further clarify the stress characteristics of the floor, Ma et al [19] used the elastic theory calculation, regarded the floor as a semi-infinite body model, and studied the evolution law of mining stress in the floor under the action of confined water. Song and Liang [20,21], based on the theory of elastic mechanics, calculated the damage form and water inrush danger area in the three-dimensional space of the floor and concluded that the water inrush danger area of the floor coincided with the maximum damage depth of the floor. The above theoretical research has a certain role in promoting and developing the damage mechanism of the floor, but it fails to consider the impact of complex factors such as actual geology and floor mining damage.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Floor Damage and Slurry Material Ratio Optimization in Deep and High Confined Water Mining

et al. 2022

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Deep mining has started in the Huaibei mining area, and the serious threat of high confined water on the floor to the coal seam is gradually increasing. Based on the deep confined water mining project at working face II633 of the Hengyuan coal mine, this paper theoretically analyzes the damage depth of the floor and the risk of water inrush from the floor. The best proportion of grouting materials was quantitatively optimized by indoor experiments, and an industrial field test was conducted to judge the grouting effect. The results show that the failure depth of the bottom plate calculated by theoretical analysis is 31.73 m; a single factor test and a response surface optimization design method determined the best value of each index: water cement ratio 0.8, bentonite 2%, water reducer 0.6%, sodium silicate 2%. The damage depth of the bottom plate after grouting is 18.83~20 m, according to the field monitoring by the strain method. The optimized slurry significantly reduces the damage depth of the floor, ensures the safe and efficient mining of the coal seam above the high–pressure water, and has a high reference value for the safe mining of the coal seam under similar geological conditions.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Floor Damage and Slurry Material Ratio Optimization in Deep and High Confined Water Mining

et al. 2022

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“…Coal is the leading energy source in China and an important industrial raw material. , Many coal mines in China have complex geological conditions; the depth of mining has been increasing in recent years, and mine water disaster seriously restricts the safe and efficient production of coal mines, − among which fault water disaster occurs in high frequencies, is highly invisible, and causes particularly severe harm. − According to statistics, more than 80% of coal floor water inrush is caused by fracture structures such as faults. − As a typical geological structure during mine production, the fault, with crack development in the coal and rock near them and damage to the native rock structure and its integrity, is very likely to become water channels between the aquifer and the coal seam under mining disturbance conditions, posing the threat of water disaster to mine production and even causing water inrush accidents, leading to economic losses and casualties . It can be seen that the fault water disaster is a severe threat to the safety of coal mine production, and it is necessary to conduct a series of studies on the fault permeability evolution and the retention of fault waterproof coal (rock) pillars.…”

Section: Introductionmentioning

confidence: 99%

Study on the Evolution of Fault Permeability and the Retention of Coal (Rock) Pillar under the Mining Conditions of Thick Coal Seam in the Footwall of Large Normal Fault

et al. 2023

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As a typical geological structure, the fault often threatens the safe mining of coal mines. In order to investigate the permeability evolution of the significant normal fault under the mining disturbance of the thick coal seam of the fault footwall and to propose a scientific and reasonable coal (rock) pillar retention plan, this paper took the YinJiaWa Fault (YJW Fa), a large normal fault, in Fucun Coal Mine, Shandong Province, China, as a research object, conducted a coupled fluid and solid simulation study on permeability evolution of the fault using COMSOL Multiphysics, based on the revealed geological data and rock mechanical parameters, and combined the theoretical calculation results to determine the width of the waterproof coal (rock) pillar. The results show that the width of the waterproof coal (rock) pillar of YJW Fa is negatively correlated with the porosity, permeability, and flow velocity of each monitoring point. With the width of 60 m as the dividing point, as the width left less than 60 m and gradually reduced to 30 m, its water-blocking capacity is destroyed, increasing the seepage velocity in the water-flowing fractured zone, forming a water channel, causing water inrush accidents. The formula and numerical simulation results are used to determine the width of the waterproof coal (rock) pillar of the YJW Fa to be 74.44−84.08 m, to ensure the safe mining of the fault footwall. This paper provides a theoretical basis for further understanding of the fault permeability development rules and safety guidance for coal seam mining of the fault footwall.

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“…The authors proposed a corresponding risk assessment equation. Song et al [26] researched the mechanism inducing groundwater outbursts through floor faults using analytical and numerical simulation methods. Moreover, Zhang et al [27] studied the hydrogeological conditions of coal mines and the potential water inrush disaster from aquifers under the coal seam, proposing a water inrush mechanism.…”

Section: Introductionmentioning

confidence: 99%

Paste Backfilling Longwall Mining Technology for Thick Coal Seam Extraction under Buildings and above Confined Aquifers: A Case Study

et al. 2022

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Backfill mining is an effective measure to control surface subsidence and restrain floor water inrush. It is an essential part of green mining technology. To solve the problem of confined water in mines under buildings, this study was carried out by combining theoretical analysis, laboratory simulation, and numerical simulation, taking the Liangbei coal mine as the research area. The coal seam floor failure characteristics of traditional longwall caving and paste filling mining methods were compared and analyzed. Based on the relevant mining theory, the key parameters, such as mining thickness and filling rate under the critical state of water inrush, were obtained. Then, the feasibility of backfill mining was expounded, and the surface subsidence of paste backfill mining was predicted and measured on site. The results demonstrated that the longwall caving mining method not only had the risk of water inrush, but also the possibility of step cracks at the surface, with the potential to result in serious damage to buildings. However, the backfill mining method reduced the floor damage depth of the coal seam from 12 m to 7 m, which reduced the water inrush coefficient by 12%, the maximum vertical concentrated stress by 42.1%, and the displacement subsidence value by 78.8%. These parameters correlated negatively with backfill strength. Meanwhile, the maximum subsidence, maximum inclined deformation, and horizontal displacement deformation were estimated as 730 mm, 2.5 mm/m, and 1.1 mm/m, respectively, consistent with the measured values (608 mm, 2.1 mm/m, and 0.9 mm/m, respectively). More relevantly, there were no obvious cracks found in the surface buildings, ensuring the safety of mining above confined water on the working face, and realizing the effective protection of surface buildings.

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Theoretical and numerical investigations on mining-induced fault activation and groundwater outburst of coal seam floor

Cited by 31 publications

References 42 publications

Experimental Study on Floor Damage and Slurry Material Ratio Optimization in Deep and High Confined Water Mining

Experimental Study on Floor Damage and Slurry Material Ratio Optimization in Deep and High Confined Water Mining

Study on the Evolution of Fault Permeability and the Retention of Coal (Rock) Pillar under the Mining Conditions of Thick Coal Seam in the Footwall of Large Normal Fault

Paste Backfilling Longwall Mining Technology for Thick Coal Seam Extraction under Buildings and above Confined Aquifers: A Case Study

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