Research on the Development Law of Water-Conducting Fracture Zone in the Combined Mining of Jurassic and Carboniferous Coal Seams

Lu, Cunjin; Xu, Jianqing; Li, Qiang; Zhao, Hui; He, Ya‐Ling

doi:10.3390/app122111178

Cited by 6 publications

(4 citation statements)

References 24 publications

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“…where H li is the height of the water conduction fracture zone, m; M is the thickness of the coal seam, m; a and b are coefficients; and c is the error parameter. The height of the water conduction fracture zone measured in multiple weakly cemented overburden mines [35,36] was used for univariate linear regression fitting to obtain the main body of the equation for the prediction of the height of the fracture zone.…”

Section: Prediction Methods Of the Height Of Water-conducting Fractur...mentioning

confidence: 99%

“…where H li is the height of the water conduction fracture zone, m; and M is the thickness of the coal seam, m. In order to verify the reliability of formula (5), the measured data of five western, weakly cemented mines were counted [33,34,36]. The results calculated by the empirical formula and the revised predicted formula were obtained, and the average values of the predicted heights were compared with the measured heights of the water conduction fracture zone.…”

Section: Prediction Methods Of the Height Of Water-conducting Fractur...mentioning

confidence: 99%

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Evolution of Water-Conducting Fracture in Weakly Cemented Strata in Response to Mining Activity: Insights from Experimental Investigation and Numerical Simulation

Liu,

Zhou,

et al. 2023

Water

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The accurate prediction of the vertical extent of water-conducting fracture (WCF) zones in weakly cemented strata is particularly significant in preventing and controlling water hazards in western coal mines. The evolution of fractures in weakly cemented strata affected by mining disturbances was comprehensively analyzed by physical similarity models, numerical simulations, and field investigations. Results indicated that the development progress of water-conducting fractures can be divided into three phases: initial slow generation, subsequent rapid development, and eventual stabilization. The numerical simulation results revealed that in the initial stage of working face mining, the development of the plastic zone is limited, and there is minimal failure in the overlying strata; therefore, fractures are slowly produced without penetrating through the strata. When the plastic zone fully encompasses the entire main roof, it triggers severe shear failure in the overlying strata, resulting in rapid fracture propagation and penetration. Once the fracture height reaches a stable state, there is no further increase in the maximum vertical displacement of key strata, indicating the extensive collapse and compaction of the overburden as well as the stabilization of the fracture heights. A modified prediction equation for WCF in weakly cemented strata was obtained by correcting the traditional empirical formula based on field investigations. This modified prediction equation enhances the accuracy in predicting fracture heights and provides a theoretical reference to address the issue of the inaccurate prediction of the water-conducting fracture height in western mine rock strata.

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Section: Prediction Methods Of the Height Of Water-conducting Fractur...mentioning

confidence: 99%

Section: Prediction Methods Of the Height Of Water-conducting Fractur...mentioning

confidence: 99%

Evolution of Water-Conducting Fracture in Weakly Cemented Strata in Response to Mining Activity: Insights from Experimental Investigation and Numerical Simulation

Liu,

Zhou,

et al. 2023

Water

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“…Roof water hazards are more prominent in the mine water disasters. The main reason is that water-conducting cracks penetrate the overlying aquifer [5,6], and underground water flows into the working sites through mining-induced cracks.…”

Section: Introductionmentioning

confidence: 99%

An Improved Back Propagation Neural Network Based on Differential Evolution and Grey Wolf Optimizer and Its Application in the Height Prediction of Water-Conducting Fracture Zone

Wang,

Zhu,

2024

Applied Sciences

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Given that the conventional back propagation neural network (BPNN) easily falls into the local optimal solutions, resulting in poor prediction accuracy, an improved BPNN based on the differential evolution and grey wolf optimizer (DEGWO) is proposed, the so-called DEGWO-BPNN. The prediction of the water-conducting fracture zone (WCFZ) height is significant for mine safety operations. A total of 104 sample data are trained and 25 sample data are tested to identify the optimal prediction model. Five evaluation indexes are selected to assess the prediction performance of the models quantitatively. Finally, the DEGWO-BPNN model is applied to a specific engineering case. The main conclusions are as follows: (1) Mining height, mining depth, coal seam dip, panel width, and ratio of hard rock as the main factors affecting the WCFZ height are selected. The topology structure of the model is defined as ‘5-12-1’; (2) the bias between the predicted value and the actual value of the training samples is smaller with an average error of 2.39. Test samples further validate the prediction precision through evaluation indexes. The values of MAE, RMSE, MAPE, and R2 are 2.3952, 3.4674, 5.3148%, and 0.99077, respectively. The prediction accuracy is 94.6852%; (3) ‘Mining Code’, MLR, BPNN, and GWO-BPNN models are treated as the comparison groups. The comparative analysis shows that the prediction performance of ‘Mining Code’ is the worst, while that of DEGWO-BPNN is the best, and it outperforms other algorithms and statistical approaches; (4) the prediction of WCFZ height in the 11601 panel is in line with the actual value. The prediction error of the DEGWO-BPNN model is lower than that of the comparison models. As such, the DEGWO-BPNN model can be well applied to the prediction of WCFZ height and is suitable for coal mines with different regional geological conditions. It can provide a valuable reference for mine safety operations.

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“…The descriptions of the deformation characteristics of the overlying strata under mines and the laws of gas emissions are mainly focused on the normal mining stage [26][27][28][29]. The study of the decisive mechanisms of mining stress transfer and surrounding rock fissure evolution on abnormal gas emissions in the special stage of initial mining must be further deepened [30,31]. By taking the 24207 working face of the Shaqu Mine as the research object, a similarity simulation experiment was conducted indoors, and the overburdened caving characteristics and the development laws of the mining-induced fracture were analyzed in the initial period of longwall mining.…”

Section: Introductionmentioning

confidence: 99%

Fracture Evolution Characteristics and Deformation Laws of Overlying Strata during the Initial Period of Longwall Mining: Case Study

Sun

et al. 2023

Sustainability

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Coal mining causes overlying rocks to collapse and be destroyed. Overburdened crevasses provide a channel for gas discharge, which is a serious safety hazard. To study the evolution characteristics and migration pattern of overburdened fissures during the initial mining period, the 24207 working face of the Shaquan mine was used as a research object. Through similar physical simulation tests, a mechanical model of the mining structure during the initial mining period was constructed to explore the factors influencing the movement pattern of the overburden strata during the initial mining period. The research results show that the evolution of mining-induced fractures in the overburdened strata in the initial mining period mainly experience the slow and rapid rising stages of the fracture dimension, while the stable mining period is in the stable development stage of the fracture dimension. The research results will help supplement and improve the theory of gas disaster prevention and comprehensive resource utilization in the initial mining stage under the mining conditions of high gas and low permeability coal seam group, achieve the goal of “coal and gas co-mining”, and ensure the safe and efficient production of mines.

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Research on the Development Law of Water-Conducting Fracture Zone in the Combined Mining of Jurassic and Carboniferous Coal Seams

Cited by 6 publications

References 24 publications

Evolution of Water-Conducting Fracture in Weakly Cemented Strata in Response to Mining Activity: Insights from Experimental Investigation and Numerical Simulation

Evolution of Water-Conducting Fracture in Weakly Cemented Strata in Response to Mining Activity: Insights from Experimental Investigation and Numerical Simulation

An Improved Back Propagation Neural Network Based on Differential Evolution and Grey Wolf Optimizer and Its Application in the Height Prediction of Water-Conducting Fracture Zone

Fracture Evolution Characteristics and Deformation Laws of Overlying Strata during the Initial Period of Longwall Mining: Case Study

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