Physical Simulation of the Water-Conducting Fracture Zone of Weak Roofs in Shallow Seam Mining Based on a Self-Designed Hydromechanical Coupling Experiment System

Zha, Hao; Liu, Weiqun; Liu, Qinghong

doi:10.1155/2020/2586349

Cited by 8 publications

(3 citation statements)

References 25 publications

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“…Because there is no accepted formula for calculating the water-conduction fracture zone in the Binchang mining area, the predicted value of the mine water surge deviates from the actual value. Mining overburden fracture zone development height prediction has become one of the impediments to engineering and scientific research because the Binchang mining area has yet to form a unified recognized formula for calculating the water-conduction fracture zone 20 . After the workface mining, the overlying rock layer in the mining void area produces tension and pressure damage and forms mining fissures and sinks.…”

Section: Introductionmentioning

confidence: 99%

Study on the damage characteristics of overburden of mining roof in deeply buried coal seam

Long

Hou

Xie

et al. 2022

Sci Rep

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The study of water-conducting fracture zone development height is key to the scientific prevention and control of water damage in mines. Based on the geological conditions of the Wenjiapo coal mine in Binchang, China, this paper investigates the development of water-conducting fracture zone in overlying bedrock during mining under large buried depth and huge thick aquifer by combining on-site well-location microseismic monitoring and laboratory similar material simulation. To overcome the limitation of the " limited outlook " of water-conducting fracture zone investigation, the spatial development characteristics of roof fissures in coal seam mining were determined by on-site " the underground - ground" combined microseismic monitoring and follow-up monitoring, and the development of overlying rock fracture under the large depth of burial was concluded. The fractures were mainly distributed in the upper part of the protective coal pillar on both sides of the working face, but less in the upper part of the working face, and primarily distributed in the protective coal pillar on the side of the working face and the adjacent mining area. To verify the accuracy of the conclusion, the overlying bedrock movement and deformation characteristics and the development process of the hydraulic fracture zone during coal seam mining were analyzed by simulating similar materials in the laboratory, using the monitored area as a prototype. The results show that the development height of the mining fracture zone obtained from microseismic monitoring is basically consistent with the simulation results of similar materials. The research finding have significant implications for the study of fracture distribution characteristics and the evolution law of mining overburden, and provide a foundation for scientific prevention and control of water damage on the roof.

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Section: Introductionmentioning

confidence: 99%

Study on the damage characteristics of overburden of mining roof in deeply buried coal seam

Long

Hou

Xie

et al. 2022

Sci Rep

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“…above the Dickenberg adit. This estimation is based on mathematical relationships between thickness of the excavated area and thickness of the overburden as previously established in Palchik (2003), Bai and Tu (2019), Guo et al (2019) and Zha et al (2020). However, additional grids with heights of 30 and 40 m are created to assess alternative values derived from these models.…”

Section: Geometry and Grid Constructionmentioning

confidence: 99%

A dual-continuum model (TOUGH2) for characterizing flow and discharge in a mechanically disrupted sandstone overburden

et al. 2022

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Underground hard coal mining usually disrupts the mechanical equilibrium of rock sequences, creating fractures within minor permeable rocks. The present study employs a dual-continuum model to assess how both fractured and porous sandstone media influence the percolation process in postmining setups. To test the approach, the software TOUGH2 was employed to simulate laminar fluid flow in the unsaturated zone of the Ibbenbüren Westfield mining area. Compared to other coal mining districts in Germany, this area is delineated by the topography and local geology, leading to a well-defined hydrogeological framework. Results reveal good agreement between the calculated and measured mine water discharge for the years 2008 and 2017. The constructed model was capable of reproducing the bimodal flow behavior of the adit by coupling a permeable fractured continuum with a low-conductivity rock matrix. While flow from the fractured continuum results in intense discharge events during winter months, the rock matrix determines a smooth discharge limb in summer. The study also evaluates the influence of individual and combined model parameters affecting the simulated curve. A detailed sensitivity analysis displayed the absolute and relative permeability function parameters of both continua among the most susceptible variables. However, a strong a priori knowledge of the value ranges for the matrix continuum helps to reduce the model ambiguity. This allowed for calibration of some of the fractured medium parameters for which sparse or variable data were available. However, the inclusion of the transport component and acquisition of more site-specific data is recommended to reduce their uncertainty.

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“…For decades, extensive research has been achieved of ground control in SBCCS. Physical simulation, numerical simulation and theoretical analysis are the main means to study the control of stope strata [10][11][12][13][14].The definition of shallow coal seam is put forward [1], with necessary definitions given for SBCCS [15]. Key indicators for the classification of SBCCS and roof activation have been established, the structure established the theory of ground control of SBCCS [15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Study on the mechanism and control of strong ground pressure in the mining of shallow buried close-distance coal seam passing through the loess hilly region

He,

Huang,

2024

Preprint

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Shallow buried close-distance coal seam (SBCCS) is widely found in northern Shaanxi, China. In the process of mining under the loess hilly area (LHA) in SBCCS, many accidents of strong ground pressure have occurred. Taking the in the Zhangjiamao Coal Mine as the background, this study revealed the mechanism of high ground pressure when the working face of lower coal seam passes through the surface loess hilly region. On-site measurements, physical similarity simulation, numerical calculation, and theoretical analysis were combined to study the mining process of SBCCS. The movement characteristics of the activated structure of the interval strata of the lower coal seam were analyzed. The dynamic load and the change pattern of the front abutment pressure (FAP) of the support during the loading stage of entering and exiting the loess hilly were determined. A coupled structural mechanics model of the overlying activated voussoir beam and the step voussoir beam rock beam of the interval strata was established, revealing the dynamic loading mechanism of strong ground pressure during passing through the LHA . The results showed that the dynamic load of the working face was the highest in areas affected by the load of the LHA, followed by the load while entering the LHA , the peak value of the FAP in the load-influenced LHA was high, which was approximately 1.12 times that after leaving the load-influenced LHA and 1.61 times that before entering this area. By establishing a mechanical model of the roof coupling structure when entering and exiting the load-influenced LHA, it was revealed that the dynamic load of the support while mining under the goaf in the LHA is mainly due to the synchronous movement of the activated structure of the collapsed roof of the upper coal seam and the interval rock structure. The load in the LHA was transmitted to the interval rock structure through the activated structure, resulting in a high dynamic load on the support. The study concluded that the determination of the support resistance of the working face should be based on the high-period compressive load of the synchronous movement of the roof structure in the loess hilly beam area. Through the engineering practice of hydraulic fracturing, the roof structure of the interval strata is changed, which can effectively reduce the dynamic pressure disaster of the working face. The research provides a scientific basis for the safe and efficient mining of shallow coalfields, and it provides reference for similar mining.

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Physical Simulation of the Water-Conducting Fracture Zone of Weak Roofs in Shallow Seam Mining Based on a Self-Designed Hydromechanical Coupling Experiment System

Cited by 8 publications

References 25 publications

Study on the damage characteristics of overburden of mining roof in deeply buried coal seam

Study on the damage characteristics of overburden of mining roof in deeply buried coal seam

A dual-continuum model (TOUGH2) for characterizing flow and discharge in a mechanically disrupted sandstone overburden

Study on the mechanism and control of strong ground pressure in the mining of shallow buried close-distance coal seam passing through the loess hilly region

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