Dynamic monitoring the deformation and failure of extra-thick coal seam floor in deep mining

Zhou, Wenlong; Zhang, Pingsong; Wu, Rongxin; Hu, Xiangyun

doi:10.1016/j.jappgeo.2019.02.007

Cited by 45 publications

(21 citation statements)

References 10 publications

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“…Three boreholes are designed in the #JZ10 drill area, and the strain gauge (Zhou et al 2019) is used to analyze the changes in the oor failure depth and failure shape associated with the mining face. According to the design drill length and the installation position of the sensor, the installation parameters of the drilling lines are shown in Table 2.…”

Section: On-site Monitoring Of the Oor Failure Depthmentioning

confidence: 99%

“…With the increasing shortage of shallow coal resources in China, the mining level of mines has extended to greater depths at 10-20 m/a Sun et al 2019). The high stress and high con ned water pressure in deep areas can easily lead to water inrush accidents (Longqing et al 2014;Zhou et al 2019), which seriously threaten the safety of production personnel (Duan et al 2012). According to incomplete statistics, China's important coal-producing areas are threatened by oor con ned water to varying degrees, and the area and severity of con ned water damage in China are the highest among the world's major coal-producing countries.…”

Section: Introductionmentioning

confidence: 99%

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Physical Modeling of Floor Failure Above Confined Water: A Case Study in China

Wang

Yuan

Chen

et al. 2021

Preprint

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Coal mining in areas with deep confined water is very dangerous; to ensure safety, it is necessary to clarify the damage characteristics of the working face floor. To directly reflect the failure characteristics of the working face floor under the coupled effects of mining stress and confined water pressure, this study takes the II633 working face of the Hengyuan coal mine in the Huaibei mining area as the engineering background. With the use of a self-designed monitoring system for confined water diversion and a similar material simulation experimental method, the mining stress distribution patterns, the deformation and failure characteristics of the overburden, and the diversion characteristics of the confined water in the working face floor are studied. The combined use of a confined water loading system and a confined water lifting system can directly reproduce the floor confined water lifting characteristics affected by floor failure during coal mining. The results show that the floor undergoes three stages of deformation in the horizontal direction: premining stress concentration compression (10-15 m ahead of the working face), postmining floor pressure relief expansion, and roof collapse stress recovery (the distance of the lagging working face is 15-20 m). In the vertical direction, a soft rock layer blocks the continuous transfer of mining stress to deeper layers and produces an important cushioning effect. In the process of coal mining, shear cracks easily develop in the coal wall in front of and behind the working face. After the coal seam is excavated, the length of the fractures that develop in the model is 27 cm. The confined water loading system can visually reproduce the hydraulic characteristics of the confined water during the mining process; that is, the confined water easily bursts at the front and back ends of the coal wall in the goaf. The error, as determined by comparison between the field measurement and the theoretical calculation results, is only 0.617 m, verifying the reliability of the similar simulation method.

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Section: On-site Monitoring Of the Oor Failure Depthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Physical Modeling of Floor Failure Above Confined Water: A Case Study in China

Wang

Yuan

Chen

et al. 2021

Preprint

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“…In order to solve the difficulties of underground structural monitoring, a series of monitoring methods for mining overburden rock mechanics based on geophysics techniques have been derived [ 6 , 7 , 8 ]. These have provided solid scientific foundation for studying the movement law of stope surrounding rocks [ 9 ], the definition of the water conducting zone [ 10 ], and the disaster-causing mechanism of rock dynamic mechanics [ 11 ]. However, with the continuous advance of the global industrial intelligent construction tide, the application of traditional means is starting to become powerless, especially in terms of automation and intelligence.…”

Section: Introductionmentioning

confidence: 99%

The Characterization Pattern of Overburden Deformation with Distributed Optical Fiber Sensing: An Analogue Model Test and Extensional Analysis

Yuan

Chai

Ren

et al. 2020

Sensors

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The evolution of overburden deformation is crucial for safety and environmental efficiency and its monitoring is becoming a key scientific issue. The use of an optical fiber sensor (OFS) for mining engineering is now receiving praise by virtue of its distinct abilities of distribution, high accuracy, and anti-interference measurement. Nevertheless, the dynamic response of OFS monitoring on overburden deformation still needs to be characterized in detail. This paper analyzed the characterization pattern of overburden deformation based on distributed optical fiber sensing (DOFS) by means of an analogue model test. Then, we discuss the influence of rules of optical fiber embedding on a model test in a numerical simulation. The results show that the DOFS monitoring demonstrates the time-space evolution of overburden deformation and the development of three horizontal areas and three vertical zones. A standardization DOFS characterization model is proposed to expound the characterization mechanism of the overburden structure zoning process; the influence of optical fiber embedding on rock displacement in the model test is revealed, and it is found that the displacement error will increase sharply when the fiber diameter is larger than 2 mm. These findings could provide an effective solution for a monitoring method in intelligent mining from the perspective of a theoretical basis and technological system.

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“…Currently, six main methods exist: multipleposition extensometer [16], borehole strain [17,18], borehole peeping [19], computed tomography electronic imaging [20,21], ground penetrating radar detection [22,23], and microseismic monitoring [24][25][26]. Owing to the wider application of optical fibers in the past two years, they have begun to be used in coal mines, e.g., the Brillouin optical time domain reflectometer to measure floor failure depth [27,28].…”

Section: Introductionmentioning

confidence: 99%

Mining Failure Response Characteristics of Stope Floor: A Case of Renlou Coal Mine

Chang

2020

Advances in Civil Engineering

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Currently, shallow coal resources are being exhausted gradually, mining depth is continuing to extend downward, and hydrogeological conditions are becoming increasingly complex. Therefore, accurate determination of the failure floor position is necessary to perform multiple-seam mining. In this study, the 7255 working face of the Renlou coal mine is regarded as the research object. Through a comprehensive measurement of ground penetrating radar detection and fixed-point grating optical fibers, the law of floor deformation and failure is analyzed dynamically, and the characteristics of the floor rock deformation response are discussed. The results of on-site monitoring indicate that the mining effect of the working face is greater than that of the tectonic stress. With the advance of the working face, the deformation of the shallow area (0–8 m) first increases gradually, then increases rapidly, and finally increases gradually again; the middle area (8–19 m) experiences three stages, from a gentle increase to temporary stability and then a rapid increase; the deep area (19–29 m) undergoes three stages, from being stable to increasing and then being stable again. After mining, the floor of the working face can be classified into four areas in the vertical direction: complete failure area (0–5 m), poor severe influence area (5–11 m), failure development area (11–19 m), and elastic deformation area (19–29 m). Mining-induced stresses cause resistance at the interface of different lithologies and weaken the effect of downward propagation. Coal seams and the interface between different lithologies are more prone to deformation. The results can provide a certain reference basis for the advanced exploration scheme of the underlying seam mining under the multiple-seam mining method, as well as provide a new approach for floor failure depth measurement.

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Dynamic monitoring the deformation and failure of extra-thick coal seam floor in deep mining

Cited by 45 publications

References 10 publications

Physical Modeling of Floor Failure Above Confined Water: A Case Study in China

Physical Modeling of Floor Failure Above Confined Water: A Case Study in China

The Characterization Pattern of Overburden Deformation with Distributed Optical Fiber Sensing: An Analogue Model Test and Extensional Analysis

Mining Failure Response Characteristics of Stope Floor: A Case of Renlou Coal Mine

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