Study on Optimization of Roadway Position in Pre-mining Upper Layered Concave–Convex Coal Body

Sun, Wei; Qin, Zhangrong; Chen, Guangbo; Li, Tan

doi:10.1007/s10706-019-00865-6

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…Zhang et al [20] built a UDEC model with dimensions of 2200 m × 550 m for evaluating the fracture development around river valleys. The value of the VJS in the above and many other studies [18][19][20][21][22][23][24][25][26][27][28][29][30] is between 1× to 3× bed thickness, but how the VJS was determined is still not clear and there is no related literature that clearly explains the determination process. To the best of the authors' knowledge, practical experiences and subjective tendencies often play a leading role, which makes it impossible to compare between different UDEC models involving different engineering cases and limits the sustainable development of such UDEC modeling strategy.…”

Section: Introductionmentioning

confidence: 87%

A Vertical Joint Spacing Calculation Method for UDEC Modeling of Large-Scale Strata and Its Influence on Mining-Induced Surface Subsidence

et al. 2021

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While universal discrete element code (UDEC) is widely used for understanding the mechanism of large-scale strata movement and the effects of mining subsidence on the environment, the fundamental knowledge of how to set vertical joint spacing (VJS) in UDEC is still not fully understood. To address the knowledge gap, we first present a novel VJS calculation method, then conduct UDEC experiments, and finally compare the predictions of UDEC models with field subsidence observation. The results suggest the following: (1) when compared to the conventional VJS setting (1× to 3× bed thickness), the maximum surface subsidence (MSS) prediction via UDEC models based on our proposed VJS setting method is closer to field observation; (2) a smaller but varying VJS setting can also have the effect of a larger VJS setting; and (3) with the increase in VJS, MSS first drops, then rises, and reaches the minimum when VJS is set at approximately 7× bed thickness. This paper provides an explanation of the VJS setting in UDEC and establishes a bridge between the KS theory and VJS, which is helpful for the sustainable development of such an UDEC modeling strategy and for a better understanding of the influences of mining subsidence on the environment in mining-affected areas.

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Section: Introductionmentioning

confidence: 87%

A Vertical Joint Spacing Calculation Method for UDEC Modeling of Large-Scale Strata and Its Influence on Mining-Induced Surface Subsidence

et al. 2021

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“…ey found that the low strength of rock around the roadway, poor mechanical properties, multiple recovery, and long-term high stress are the main reasons for the overall instability of the roadway: strengthening the integrity of the surrounding rock of the roadway and the key parts (coal pillar and roof ) is key to the control of the surrounding rock. Yan, Song, Sun, Liu, Chen, Cheng, and Kong et al [18][19][20][21][22][23][24] studied the stress field and plastic zone failure of the upper seam under the condition of multiple closely spaced coal seams and proposed that the roadway should be arranged in the stress reduction zone. Wang, Dong, Guo, He, and Hao, Tu, Qin, Liu, Zhao, Jiang et al [25][26][27][28][29][30][31][32][33][34] determined the main factors influencing roadway deformation and failure during the recovery process and proposed that the roadway layout and surrounding rock control are effective measures with which to maintain the stability of the roadway.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Optimal Layout of the Roadway in Closely Spaced Ultra‐Thick Coal Seams Mining with Remaining Coal Pillars

Gao

Tian

et al. 2021

Shock and Vibration

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The reasonable layout of the roadway in closely spaced, ultra-thick coal seam mining is of great significance to mining safety. Based on the research background of repeated roof leaks in the process of repairing the return air roadway in working face No. 30503 in the Tashan Coal Mine, theoretical analysis, in situ engineering testing, and numerical simulation were jointly adopted to evaluate the stability of the return air roadway under two schemes of repairing the original return air roadway and excavating a new return air roadway. The results show that the vertical mining-induced fissure above the roadway will cause severe damage to the roadway due to the influence of working-face mining when restoration of the roadway excavation is adopted. When choosing to excavate a new return air roadway, the new return air roadway just staggers the vertical cracks located in the top slab of the original return air roadway, putting the roadway in a state of stress reduction, making the roadway itself more stable and conducive to support. Therefore, the new air return tunnel was selected to establish the working face. To ensure safety of the working face during the mining of the original return air roadway, the original return air roadway was filled with high water content materials. Site investigation data show that this material plays a cushioning role in the filling section of the original return air roadway during the mining of the 30503 working face, and the deformation of the new return air roadway during the filling section crossing the original return roadway is stable and well controlled.

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Roof Bolting Anchoring Performance Research on the Entry under the Gob of Close-Distance Coal Seam

Yang

Huang

Ji³

2022

Geofluids

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Seam spacing plays a crucial role in selecting roof bolting of the close-distance coal seam. This work utilized three methods to determine the minimum roof bolting seam spacing of the lower coal seam (LCS) entry after the upper coal seam (UCS) mining. Based on the entry of the No.3-2 coal seam (LCS) in Chaili Coal Mine in China, theoretical analysis, pull-out bolt test, and numerical simulation were performed to calculate the maximum floor failure depth of the UCS and to determine the minimum seam spacing of the roof bolting. The maximum floor failure depth of the UCS determined through theoretical analysis and numerical simulation is 3.2 m and 3.3 m, respectively. In general, the anchorage length of rock bolting is less than 2.4 m, so the minimum seam spacing is 5.6 m or 5.7 m. To further determine the anchorage performance of the roof, the pull-out test was employed on the entry roof of the LCS. When the seam spacing is no less than 6 m, the test results show that the pull-out force of the bolt is more significant than 30kN; in addition, the numerical simulation results indicate that the roof-to-floor and rib-to-rib convergence are relatively small. Therefore, the LCS entry’s minimum roof bolting seam spacing can be determined as 6 m. This study could be used to select and design roof bolting under similar close-distance coal seam conditions.

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Study on Optimization of Roadway Position in Pre-mining Upper Layered Concave–Convex Coal Body

Cited by 3 publications

References 14 publications

A Vertical Joint Spacing Calculation Method for UDEC Modeling of Large-Scale Strata and Its Influence on Mining-Induced Surface Subsidence

A Vertical Joint Spacing Calculation Method for UDEC Modeling of Large-Scale Strata and Its Influence on Mining-Induced Surface Subsidence

Investigation of the Optimal Layout of the Roadway in Closely Spaced Ultra‐Thick Coal Seams Mining with Remaining Coal Pillars

Roof Bolting Anchoring Performance Research on the Entry under the Gob of Close-Distance Coal Seam

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