Fracture criterion of basic roof deformation in fully mechanized mining with large dip angle

Yang, Ke; Wei, Zhen; Chi, Xiaolou; Gao, Ansen; Fu, Qiang

doi:10.1177/0144598720986628

Cited by 11 publications

(6 citation statements)

References 22 publications

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“…For super large working face mining, it is difficult to fully 3 Geofluids define the problem by solving a single plane problem. Therefore, the roof of the coal seam is regarded as a plate structure, and the initial caving step length and the periodic caving step length of each roof stratum are calculated according to plate theories [25], as shown in Figure 2.…”

Section: Calculation Of Cavingmentioning

confidence: 99%

Roof Fracture Characteristics and Strata Behavior Law of Super Large Mining Working Faces

et al. 2021

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Exploiting the working face in coal mines using a super long mining length and large mining height has become important for intensive production with high yield and high efficiency. The paper develops a roof structure model to analyze the influence of 195 m, 242.4 m, and 376 m working face lengths at large mining height in Wangzhuang Coal Mine in China as the case study. The roof fracture characteristics, migration law, and strata behavior law under different working face lengths are compared and studied by numerical simulation, and the reliability of support selection in the working face at large mining height is analyzed by field measurement statistics. The results show that the roof fracture mode of a super large working face is a successive layered fracture. The length of the working face has little effect on the roof fracture step length, and the fracture step length is positively correlated with the thickness of the rock stratum. The roof subsidence law for a super large working face is different from the intermittent subsidence of the unimodal Gaussian distribution curve of ordinary working faces, which shows the intermittent subsidence of multiple ordinary working faces. The roof periodic weighting of a super large working face, which fluctuates violently within 100 m at both ends, is more drastic than that of an ordinary working face as a whole. Field statistical analysis shows it is more appropriate to choose high-strength support for a super large working face.

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Section: Calculation Of Cavingmentioning

confidence: 99%

Roof Fracture Characteristics and Strata Behavior Law of Super Large Mining Working Faces

et al. 2021

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“…Lai et al (Lai et al, 2021) used a research method that combines similarity simulation experiments, numerical simulations, and on-site monitoring to analyze the migration law of overlying strata and the distribution characteristics of fracture zone in coal seam mining under thick and loose layers. Yang et al (Yang et al, 2021) derived a formula based on the thin plate theory for calculating the basic roof stress distribution in highly inclined coal seams. Xu et al (Xu et al, 2018) derived a formula for calculating the fracture angle of the overlying strata in a horizontal coal seam goaf based on the theory of key layers, and verified the rationality and reliability of the formula through physical simulation experiments.…”

Section: Introductionmentioning

confidence: 99%

Research and application of ‘three zones’ range within overlying strata in goaf of steep coal seam

Yang,

Xu,

Liu

et al. 2024

Front. Energy Res.

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The determination of the ‘three zones’ range within the overlying strata in goaf of paramount importance for effective gas extraction in the goaf and the prevention and control of gas levels exceeding limits in both the working face and the upper corner. Due to the influence of their dip angles, the existing formula used to calculate the breaking boundary angle of the overlying strata in the goaf of horizontal coal seams is no longer suitable for steep coal seams. In response to this issue, the movement law of the overlying strata during the mining of steep coal seams was analyzed and a formula for calculating the breaking boundary angle of the overlying strata in the goaf of steep coal seams was derived. The theoretical calculation formula was applied to the 3,103 fully mechanized mining face of a certain mine in southwest China, and compared and analyzed the results with numerical simulation and on-site measurement using microseismic monitoring technology. The research findings demonstrate that the formula effectively quantifies the ‘three zones’ range within the overlying strata in the goaf of steep coal seams. The ‘three zones’ range in steep coal seams is primarily influenced by factors such as the length of the filling area in the lower part of the goaf, changes in roof lithology, coal seam dip angle, length of the working face, and overburden load. The longer the length of the filling area, the larger the upper breaking boundary angle and the smaller the lower breaking boundary angle of the fracture zone. Based on the research results of three methods, the height of the caving zone in the 3,103 fully mechanized mining face is from 6.93 m to 7.7 m, the height of the fracture zone is from 28.91 m to 34.2 m, the lower breaking boundary angle of the fracture zone is from 40° to 44.5°, and the upper breaking boundary angle of the fracture zone is from 57.7° to 62°. The research results offer robust technical support and theoretical guidance for the determination of the ‘three zones’ range within the overlying strata during the future mining of steep coal seams.

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“…The coal-forming environment of steeply dipping coal seams is complex, and safe and efficient mining is tough. In recent years, many experts, scholars, and engineers have carried out research and exploration on the problems of mine pressure behavior law (Wang et al, 2022; Yang et al, 2021; Tu et al, 2017), distribution characteristics and spatial distribution of surrounding rock stress (Dai et al, 2006; Wei et al, 2021; Wang et al, 2020; Wu et al, 2020a), asymmetric deformation and failure movement law of roof and floor strata and rock mass structure (Wu et al, 2021; Li et al, 2022; Luo et al, 2021, 2023; Chi et al, 2021; Shi et al, 1993; Li et al, 2022), surface subsidence caused by coal seam mining (Yin et al, 2001; Xie et al, 2020), coupling mechanism, and stability control of “support-surrounding rock” system (Hao et al, 2021; Wang et al, 2017; Xie et al, 2020; Zhang et al, 2023; Zhao et al, 2022; Yang et al, 2020; Wang et al, 2018), sliding and toppling mechanism of support and equipment (Chi et al, 2020; Zhang et al, 2008; Yang et al, 2018) and possible surrounding rock disasters. It has promoted the continuous progress of the theory and technology of longwall mining in steeply dipping coal seams, and greatly improved the poor safety of mining in steeply dipping coal seams.…”

Section: Introductionmentioning

confidence: 99%

Study on roof breaking mechanism and support stability of steeply dipping seam and large mining height

Hu,

Xie,

Huang

et al. 2023

Energy Exploration & Exploitation

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Taking the steeply dipping and large mining height working face of a mine as the engineering background, through the combination of physical simulation experiment, numerical calculation, theoretical analysis and field monitoring, based on a comprehensive analysis of the deformation and failure characteristics of the macrostructure of surrounding rock, the roof breaking mechanism and support instability characteristics of large mining height working face under the angle effect are studied. The research shows that due to the influence of the dip angle of the coal seam, the roof stress is asymmetrically deflected along the tendency, and the load of the overlying strata is transmitted to the upper and lower coal bodies with the stress-deflection boundary as the boundary, resulting in the deformation and failure of the roof and the filling showing obvious asymmetric characteristics. With the increase of dip angle, the asymmetric characteristics of roof stress transfer are enhanced, the stress release arch is reduced, the height of caving zone is reduced, the deformation and failure area is gradually moved up, and the regional characteristics of roof loading and deformation and failure are more obvious, which leads to the significant increase of unbalanced loading degree and instability probability of supports in different areas. Combined with the actual production, the prevention and control measures of hard roof caving and support crushing in fully mechanized mining face with steeply dipping seam and large mining height are put forward.

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Fracture criterion of basic roof deformation in fully mechanized mining with large dip angle

Cited by 11 publications

References 22 publications

Roof Fracture Characteristics and Strata Behavior Law of Super Large Mining Working Faces

Roof Fracture Characteristics and Strata Behavior Law of Super Large Mining Working Faces

Research and application of ‘three zones’ range within overlying strata in goaf of steep coal seam

Study on roof breaking mechanism and support stability of steeply dipping seam and large mining height

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