Failure of bolt support and experimental study on the parameters of bolt-grouting for supporting the roadways in deep coal seam

Pan, Rui; Wang, Q.; Jiang, Bei; Li, S.C.; Sun, Huibin; Qin, Q.; Yu, Hao; Lü, Wei

doi:10.1016/j.engfailanal.2017.06.025

Cited by 70 publications

(25 citation statements)

References 18 publications

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“…The discontinuous area in ultra‐thick coal seams with parting is likely to occur separation . Then under the influences of underground pressure, the chamber is extremely easy to occur rib spalling and roof falling, thus increasing the difficulty in chamber support …”

Section: Introductionmentioning

confidence: 99%

“…5,6 Then under the influences of underground pressure, the chamber is extremely easy to occur rib spalling and roof falling, thus increasing the difficulty in chamber support. 7,8 Currently, many researches on large-section chamber or roadway support have been carried out. Fan et al 9 used the numerical method to study the blasting-induced plastic failure of large-section chamber surrounding rocks.…”

Section: Introductionmentioning

confidence: 99%

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Failure characteristics and control technology for large‐section chamber in compound coal seams—A case study in Tashan Coal Mine

Tai

Xia

Kuang

2019

Energy Science & Engineering

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The coal production exploited from extra‐thick coal seams accounts for 45% of China's total coal production. With large coal output, the extra‐thick coal seams require that the chamber section be more than 100 m2. In case of parting (the noncoal rock, usually mudstone, sandwiched in the coal seam) in the extra‐thick coal seams, the integrity of the coal seams will be damaged and the large‐section chamber is extremely easy to occur rib spalling and roof leakage, which will increase the chamber's supporting difficulty. To solve such problems, this paper took the electromechanical chamber in Tashan Coal Mine as the engineering background and analyzed the deformation and failure characteristics of this chamber surrounding rocks by the numerical simulation method during the excavation process. The results indicated that the failure areas of surrounding rocks were mainly in partings, chamber ribs, and chamber dome with the failure depths of 15 m, 10 m, and 5 m, respectively. Based on the obtained deformation and failure characteristics, the supporting method of grouting integrated with high‐strength bolts and anchor cables was put forward. The grouting method was firstly used to improve the integrity of the chamber surrounding rocks, and the high‐strength bolts and anchor cables were used for supporting. Then, the supporting parameters of the bolts and anchor cables and the grouting parameters were optimized by the numerical simulation method. The optimized parameters were applied in the electromechanical chamber in Tashan Coal Mine, and the on‐site chamber ribs lateral displacement and roof separation amounts were only 0.018 m and 0.012 m, respectively, indicating that the surrounding rocks were controlled effectively.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Failure characteristics and control technology for large‐section chamber in compound coal seams—A case study in Tashan Coal Mine

Tai

Xia

Kuang

2019

Energy Science & Engineering

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“…Since the increase in bolt length causes also increases in the stresses induced in the bolt steel material, the steel failure becomes possible instead of the sliding at the friction surface. The increase in the bolt length sometimes has not a positive effect on the load capacity, because the strength of the bolt steel material can make limitations in case of using high bolt lengths [29][30][31][32]. The maximum bolt length was 5 m in this study.…”

Section: Discussionmentioning

confidence: 91%

Length Effect on Load Bearing Capacities of Friction Rock Bolts

Komurlu

Demir

2019

Period. Polytech. Civil Eng.

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Change in the load bearing capacity of the split set type friction rock bolts with variations of bolt lengths was investigated within this study. To determine a relation between the load bearing capacity and bolt length parameters, different friction bolt models with various lengths were analyzed with a numerical modelling study. In addition, a series of pull-out tests was carried out to evaluate the load bearing capacities of the split set type friction rock bolts with different lengths. The load bearing capacity of the bolts was found to decreasingly increase with the increase in the bolt length. As an outcome of this study, a relation between the load bearing capacity and rock bolt length parameters is suggested in accordance with the results obtained from both numerical and experimental studies.

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“…Researchers have developed some techniques to improve the bearing capacities of the surrounding rocks and reduce the convergence of roadways developed under high‐stress environment . Those techniques include the pumpable cribs, the strong rib/roof bolting, and many others summarized in Peng .…”

Section: Introductionmentioning

confidence: 99%

“…1,6 Researchers have developed some techniques to improve the bearing capacities of the surrounding rocks and reduce the convergence of roadways developed under high-stress environment. 1,[7][8][9][10][11] Those techniques include the pumpable cribs, the strong rib/roof bolting, and many others summarized in Peng. 12 However, field observations indicate that those techniques often have limited effects upon reducing the large deformation of surrounding rocks, primarily because the artificial reinforcement is far more uncompetitive to the | 1405 WANG et Al.…”

Section: Introductionmentioning

confidence: 99%

Depressurizing boreholes for mitigating large deformation of the main entry

Wang

Zheng

Shen

et al. 2019

Energy Science & Engineering

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The main entries in longwall coal mine frequently encounter large deformation, depending on the stress environment. Depressurizing boreholes are applicable to reduce the large deformation; however, it is difficult to determine the proper parameters (diameter and spacing) for an effective implementation. This study aims to propose feasible design criteria for the quantification of those parameters. We first developed a rigorous numerical model, for a roadway in Zhangshuanglou coal mine, using the rock mechanical properties determined from extensive laboratory measurements and analyses. We then investigated the dependency of the stress transfer and roadway deformation on the ratio of borehole diameter and spacing (D/R and D/I). The symbols of D, R, and I represented the diameter, row spacing, and interspacing of the boreholes, respectively. We found that (a) D/R has to be between 1:6 and 1:2; and (b) D/I has to be between 1:6 and 1:4, for sufficient depressurization in the surrounding rocks. The optimized borehole diameter and spacing parameters were applied in the field where the deformation of roadway was significantly reduced. Finally, we proposed a criterion to determine those parameters of depressurization boreholes for application in other geological and mining conditions.

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Failure of bolt support and experimental study on the parameters of bolt-grouting for supporting the roadways in deep coal seam

Cited by 70 publications

References 18 publications

Failure characteristics and control technology for large‐section chamber in compound coal seams—A case study in Tashan Coal Mine

Failure characteristics and control technology for large‐section chamber in compound coal seams—A case study in Tashan Coal Mine

Length Effect on Load Bearing Capacities of Friction Rock Bolts

Depressurizing boreholes for mitigating large deformation of the main entry

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