Study on the movement characteristics of the overlying stratum and surrounding rock control in ultraclose coal seams: A case study

Zhu, Liu; Yao, Qiangling; Xia, Ze; Wang, Wei-Nan; Li, Xuehua

doi:10.1002/ese3.581

Cited by 13 publications

(8 citation statements)

References 49 publications

(65 reference statements)

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“…To test the fracturing effect, microseismic monitoring was carried out for the fracturing process. Since the 1970s [23,24], microseismic monitoring technology has been extensively investigated and applied domestically and abroad. is technology has achieved many practical results in production and can be used to monitor the shape of the fracture space, effective fracture length, fracture height, and in situ stress distribution of the fracturing well.…”

Section: Seismic Crack Monitoring Technologymentioning

confidence: 99%

Prevention Technology for Strong Mine Pressure Disaster in the Hard-Roof Large-Mining-Height Working Face

Duan

Zhao

2020

Shock and Vibration

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The movement and destruction of the hard roof in a stope is an important reason for the occurrence of strong ground pressure disasters at the working face. Considering Tongxin Coal Mine as the engineering background, the stress distribution law of the surrounding rock and the overburden rock damage characteristics of a large-mining-height working face under the hard roof were investigated. To solve the problem whereby the stope’s hard roof is difficult to collapse, the hard rock key stratum of the roof was hydraulically fractured to weaken the mechanical properties of the roof rock stratum. Additionally, microseismic monitoring technology was used to monitor the cracking effect of the rock stratum. The theoretical calculation and numerical simulation results reveal that, after hydraulic fracturing, a crack with a more consistent trend formed inside the hard rock stratum and a large area of the rock stratum was damaged. According to the monitoring results of the stope stress after hydraulic fracturing, the law governing the occurrence of the leading bearing pressure was in effect. In contrast, the influence range and peak strength of the leading bearing pressure were considerably reduced at the working face after hydraulic fracturing. After performing hydraulic fracturing on the roof of the working face, the bearing pressure of the working face can satisfy the production requirements better. Finally, the results obtained through this study can be used as a reference for determining the width of coal pillars under similar mining conditions.

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Section: Seismic Crack Monitoring Technologymentioning

confidence: 99%

Prevention Technology for Strong Mine Pressure Disaster in the Hard-Roof Large-Mining-Height Working Face

Duan

Zhao

2020

Shock and Vibration

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“…However, with the high-intensity exploitation in recent years in China, the reserves of coal seams that are easily minable in many mining areas are diminishing continuously. (Zhu, Yao, et al, 2020) The coal reserves with the less favorable geological condition, such as close coal seams, are coming into focus. (Feng and Wang, 2020, Gao, Zhang, et al, 2020, Sushe and Weibing, 2016, Wang, Chang, et al, 2018) Due to the widely distributed and abundant reserves in China, the mining of close coal seams is regarded as an effective means to improve the recovery of coal resources.…”

Section: Introductionmentioning

confidence: 99%

“…(Feng and Wang, 2020, Gao, Zhang, et al, 2020, Sushe and Weibing, 2016, Wang, Chang, et al, 2018) Due to the widely distributed and abundant reserves in China, the mining of close coal seams is regarded as an effective means to improve the recovery of coal resources. (Zhu, Yao, et al, 2020, Li, He, et al, 2020, Shang, Ning, et al, 2019)…”

Section: Introductionmentioning

confidence: 99%

Research and application of Gob-Side entry retaining with roof presplitting under residual coal pillar of upper coal seam

Tian

Wang

et al. 2022

Energy Exploration & Exploitation

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In the mining of close coal seam, the stress concentration under the residual coal pillar in the upper coal seam leads to serious deformation to roadway surrounding rock in the lower coal seam. Hence, it poses a huge challenge to the maintenance of entry surrounding rock. Based on this, an approach of entry surrounding rock control technology, directional pre-splitting, and roof-cutting pressure relief, was applied. The stress and deformation of entry surrounding rock utilizing directional pre-splitting and roof-cutting pressure relief were studied by numerical simulation and field test The results indicated that the depth of stress concentration under the residual coal pillar achieve 44 m. With the application of the roof presplitting, the vertical stress of the entry roof decreased. Utilizing the roof presplitting with a height of 7 m and an angle of 15°, the gangue filled the goaf and supported the overlying strata. Meanwhile, the surrounding rock of entry was controlled with a constant resistance anchor cable (9 m length) and gangue prevention support structure. Through field test monitoring, the roof pressure and the deformation of surrounding rock increases rapidly at 30 ∼ 110 m behind the working face. From 110 ∼ 160 m, the increased rate of roof pressure and surrounding rock deformation gradually slows down and tends to be stable at 160 m behind the working face. The maximum displacement of the roof to the floor is 511 mm, and the maximum displacement of the gangue rock wall to coal wall is 421 mm. The remaining roadway meets the demand of the adjacent working face.

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“…11 In coal mines containing multiple coal seams, protective coal layer (PCL) mining is the most economical and effective regional gas disaster control and prevention method. [12][13][14][15][16] Moreover, the mining of PCL also provides a conducive condition for CBM drainage due to the gas pressure-relief effect. Therefore, occasionally, in China, even in cases where there are no appropriate PCLs, mining of nearly whole soft rock is adopted as a PCL.…”

Section: Introductionmentioning

confidence: 99%

Physical simulation of upper protective coal layer mining with different coal seam inclinations

Fang

Shu

Wang

2020

Energy Science & Engineering

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Protective coal layer (PCL) mining is a preferred regional method for preventing coal and gas outbursts; stress‐relief of PCL mining is the prerequisite of pressure‐relief gas drainage. In order to study the stress‐relief effect of PCL mining on protected coal seams and determine the protection scope of PCL mining under different inclinations, this paper uses physical simulations to study the stress‐relief law and deformation characteristics of the strata during upper PCL mining with a gentle inclination (25°), an intermediate inclination (45°), and a steep inclination (65°). The results show that as the coal seam dip increases, the degree of deformation and failure of the overburden strata gradually decreases, the severe subsidence and expansion area of the overburden strata tends to gradually develop in the uphill direction of the working face, and the floor strata underlying the protective seam significantly expand toward the goaf. However, the absolute value of the upward movement of the floor strata is much smaller than that of the roof strata; and the greater the dip angle, the greater the ratio of floor displacement to roof subsidence. The stress‐relief curve of the protected layer is approximately U‐shaped. As the inclination of the coal seam increases, the stress‐relief range decreases gradually. The maximum relief‐stress and the stress release coefficient of the protected layer initially increase and then decrease. The stress concentration coefficient of the protected coal seam initially increases first and then decreases in both uphill and downhill of the working face in the PCL. As the inclination increases, the stress‐relief angle of the downhill boundary initially increases and then decreases, while the stress‐relief angle of the uphill boundary decreases gradually. Our research results provide guidance for the delimitation of the protected scope of PCLs with different dip angles.

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Study on the movement characteristics of the overlying stratum and surrounding rock control in ultraclose coal seams: A case study

Cited by 13 publications

References 49 publications

Prevention Technology for Strong Mine Pressure Disaster in the Hard-Roof Large-Mining-Height Working Face

Prevention Technology for Strong Mine Pressure Disaster in the Hard-Roof Large-Mining-Height Working Face

Research and application of Gob-Side entry retaining with roof presplitting under residual coal pillar of upper coal seam

Physical simulation of upper protective coal layer mining with different coal seam inclinations

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