Failure Mechanism and Control of Lower Retracement Channel in Close‐Distance Double‐Thick Coal Seams

He, Fulian; Lv, Kai; Li, Xiaobin; Qin, Binbin; Li, Liang

doi:10.1155/2021/6651099

Cited by 14 publications

(10 citation statements)

References 29 publications

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“…Therefore, the double‐yield model was used to simulate the mechanical properties of gob gangue. The double‐yield parameters were obtained by using trial and error, 33 as shown in Tables 3 and 4. Numerical model validation…”

Section: Numerical Simulation Analysis On Deformation and Failure Mec...mentioning

confidence: 99%

Field and simulation study of the rational retracement channel position and control strategy in close‐distance coal seams

et al. 2022

Energy Science & Engineering

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Different from single coal seam mining, the stress evolution in the end mining stage of close-distance coal seams is extremely complex. The unreasonable position and support of the lower retracement channel will cause serious deformation and damage to the surrounding rock. Taking the Yanzishan coal mine as the engineering background, the deformation and failure characteristics of the retracement channel under different overlay environments and the key influencing factors of position design were discussed by numerical simulation, theoretical analysis, and field investigation. The results show that the coupling superposition of upper coal pillar high stress and mining dynamic pressure will form a dangerous area with severe ground pressure behavior. The retracement channel should be preferentially designed in zone A (overlying mining roadways), followed by zone B (overlying end-mining coal pillar), and finally, zone C (overlying section coal pillar). In addition, the rational horizontal distance between the lower retracement channel and the upper end-mining coal pillar should make the channel in a good stress environment. The safety distance between the retracement channel and the nearest main roadway (end-mining coal pillar width) should be greater than the severe range of advance abutment pressure. Finally, the design principle and control strategy for the lower retracement channel is proposed. The feasibility and rationality of the study are verified by industrial applications.

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Section: Numerical Simulation Analysis On Deformation and Failure Mec...mentioning

confidence: 99%

Field and simulation study of the rational retracement channel position and control strategy in close‐distance coal seams

et al. 2022

Energy Science & Engineering

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“…Many scholars have widely researched on ground pressure in the working face of close-distance coal seams [11][12][13]. Shang studied the destruction process of the lower coal seam chain pillar and gate road under the action of the coal pillar in close-distance coal seam mining [14].…”

Section: Introductionmentioning

confidence: 99%

Study on the Key Factors of Terminal Mining Line Layout in Repeated Mining of Close-Distance Thick Coal Seams

Liu

et al. 2022

Advances in Materials Science and Engineering

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In order to mater the reasonable layout basis of the terminal mining line position in the repeated mining of close-distance thick coal seams, taking Yan mine as the engineering background, we conducted theoretical analyses, numerical simulations, and field measurements to study the action mechanism of the stress arch. The results show that (1) with repeated mining, the shape of the left and right half arches of the stress arch changes in the order of time and space until it is stable; (2) the shape of the stress arch is highly related to the distribution of abutment pressure in the working face. If the shape is unchanged, the distribution of abutment pressure is unchanged; (3) in the final mining stage of repeated mining, when the shape of the right half arch is stable, the difference stagger distance of the terminal mining line has little effect on the distribution of abutment pressure of the working face where the front arch foot is located; (4) when the internal stagger distance between 3216 working face and terminal mining line of 4216 working face is greater than 22 m or the external stagger distance is greater than 30 m, 3216 working face is located in a relatively safe position. This study clarifies the key factors for the layout of terminal mining lines in close-distance thick coal seams, which can provide a scientific basis for similar projects.

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“…[19][20][21] During the working face life cycle, it is indispensable to safely and efficiently mine extra-thick coal seams while stopping and withdrawing the supports at a suitable location is the most crucial step to end the cycle. [22][23][24] The stopping mining line of the working face is also called the terminal mining line, which is the position where the longwall working face stops coal mining and withdraws the supports. 25 The supports are evacuated from the retracement channel, and the supports' area and the channel's area form a large section of the roadway during the stopping period (LSRSP).…”

Section: Introductionmentioning

confidence: 99%

“…During the working face life cycle, it is indispensable to safely and efficiently mine extra‐thick coal seams while stopping and withdrawing the supports at a suitable location is the most crucial step to end the cycle 22–24 . The stopping mining line of the working face is also called the terminal mining line, which is the position where the longwall working face stops coal mining and withdraws the supports 25 .…”

Section: Introductionmentioning

confidence: 99%

Reasonable stopping method and retracement channel support at fully mechanized top coal caving working face of 15 m extra‐thick coal seam: A case study

Xie

et al. 2022

Energy Science & Engineering

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Extra-thick coal seams are widely distributed in the Datong mine area in China. The rapid stopping of mining and the support withdrawal technology for extra-thick coal seams need to be developed urgently. The reasonable stopping top coal caving distance, main roof's fracture line position, and large section roadway during the stopping period (LSRSP) support method of the header face of 15 m extra-thick coal seam are systematically studied by using field measurement, experiment, numerical simulation, and similar material simulation methods. With the increase in stopping coal caving distance, the range of the medium and low displacement zone of the LSRSP overburden gradually expands. In contrast, the depth of the plastic zone decreases. The scope and intensity of the high-stress area of the overlying rock in front gradually decrease and shift from deep to the outside, while the peak stress area shifts from the top coal area to the coal rib of the retracement channel.Comparing the stopping of medium-thick and thick coal seam working face, the interaction between "main roof−unmined top coal−supports" is analyzed.The unique characteristics of the extra-thick coal seam working face are derived: when the stopping coal caving distance is shorter than the length of the key block, the dropped coal body cannot effectively restrict the movement of key blocks. Mutual compression and subsidence occur between key blocks, making the broken coal rock block squeeze into the supports. By the simulation study of each index, the stopping coal caving distance of the extrathick coal seam is optimal when it is slightly larger than the length of the key block (i.e., the periodic weighting step), simultaneously, the main roof fracture line behind the supports is most favorable for stopping mining. After ensuring the stability of the LSRSP's overburden structure, the differentiated support scheme of "controlled zoning−strength grading" was proposed, and the

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Failure Mechanism and Control of Lower Retracement Channel in Close‐Distance Double‐Thick Coal Seams

Cited by 14 publications

References 29 publications

Field and simulation study of the rational retracement channel position and control strategy in close‐distance coal seams

Field and simulation study of the rational retracement channel position and control strategy in close‐distance coal seams

Study on the Key Factors of Terminal Mining Line Layout in Repeated Mining of Close-Distance Thick Coal Seams

Reasonable stopping method and retracement channel support at fully mechanized top coal caving working face of 15 m extra‐thick coal seam: A case study

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