Deformation and fracture at floor area and the correlation with main roof breakage in deep longwall mining

Li, Chunyuan; Zuo, Jianping; Shi, Yanchao; Wei, Chunchen; Duan, Yuqing; Zhang, Yong; Hong, Yiguo

doi:10.1007/s11069-021-04656-2

Cited by 16 publications

(4 citation statements)

References 31 publications

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“…Floor failure in coal mining will form a plastic-yield zone, unloading-failure zone, unloading-expansion zone, gangue-damage zone, and pre-peak-damage zone [24]. Combined with the near-field rock-strata control theory [34][35][36], it can be determined that the masonry-beam structure can easily be formed at the end of a working face after basic roof failure. Therefore, the floor-failure characteristics of the inclined goaf roadway in deep mining at all stages are shown in Figure 7.…”

Section: Stress Environment and Floor Asymmetric-failure Characterist...mentioning

confidence: 99%

Mechanism and Control of Asymmetric Floor Heave in Deep Roadway Disturbed by Roof Fracture

Wei

Zhang

et al. 2023

Sustainability

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In view of the serious problem of bottom-drum damage in deep mining along empty roadways, the asymmetric bottom-drum damage characteristics and control mechanisms of deep mining along an empty roadway were studied using the trackway of the 11060 working face in Zhao Gu II mine as the research background. Based on the slip-line theory, support-pressure distribution law, and Griffith’s damage-criterion theory, the mechanism of asymmetric bottom drums and the maximum fracture-development depth of the bottom plate in a deep roadway under top-plate fracture perturbation were analyzed. The 3DEC discrete-element software was used to simulate and analyze the characteristics and evolution of the asymmetric bottom bulge of the roadway under dynamic-load disturbance, and the asymmetric control scheme of “slurry anchor reinforcement + top cutting and pressure relief” was proposed. The results show that, under the influence of static load of deep high-abutment pressure and the dynamic-load impact of the instability of the masonry-beam structure under periodic pressure of the adjacent working face, the deep-mining goaf roadway was prone to producing asymmetric floor heave. The floor-heave degree and maximum fracture-development range of the roadway in the affected area under the influence of dynamic load > those in goaf roadway > those in the roadway in the stable area affected by tunneling. The distribution of stress, displacement, and maximum floor heave was skewed to the side of the coal pillar in the goaf, showing an inverted right oblique V shape. The asymmetric floor heave of a roadway can be effectively controlled by grouting anchor-cable reinforcement (increasing the anti-damage limit) and roof-cutting pressure relief (cutting off the dynamic-load source). The research results can provide an important reference for the control of roadway floors under similar geological conditions.

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Section: Stress Environment and Floor Asymmetric-failure Characterist...mentioning

confidence: 99%

Mechanism and Control of Asymmetric Floor Heave in Deep Roadway Disturbed by Roof Fracture

Wei

Zhang

et al. 2023

Sustainability

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“…Song et al [14][15][16] established the stress model of the floor based on the elastic theory, and obtained the stress distribution and failure form of the floor through theoretical derivation and calculation. Li et al [17][18][19] focused on the failure behavior of floors influenced by coal mining in deep mines. According to the theory of unloading mechanics and damage mechanics, the compression shear failure and unloading failure mechanical behavior of floor under mining disturbance is studied, and the partition of floor disturbance failure is divided.…”

Section: Introductionmentioning

confidence: 99%

Study on the effect of rock stratum structure on the stability of weakly cemented layered floor and the floor control measures: A case study of Meihuajing Mine

Zhu

Hua

et al. 2023

Energy Science & Engineering

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Given the deformation and instability of the layered floor of weakly cemented soft rock roadway, taking the mining roadway of Meihuajing Mine as the engineering background, the deformation and instability mechanism of the floor and the control measures of the surrounding rock under different stratum combination conditions are studied by using the methods of field investigation, numerical calculation and field test. The results show that: (1) the layered characteristics of surrounding rock in weakly cemented soft rock roadways are significant, and the combination structure of floor rock strata is complex and changeable. Under the influence of engineering disturbance, the roadway has a tendency of large deformation, especially floor heave. (2) The buckling instability of the layered floor is caused by the layered weakening effect, and the unstable zone, the substable zone and the stable zone are formed successively from the shallow to the deep. With the increase of the layer thickness, the integrity of the layered floor is improved, the layered weakening effect is reduced, and the overall stability of the layered floor is improved. (3) The existence of weak interlayer further degrades the integrity of layered floor, and the progressive failure of floor rock mass layer by layer is more significant under the influence of layered weakening effect. (4) The relatively hard rock stratum in the composite structure plays an important role in controlling the deformation and failure of the floor, playing the role of “local key stratum.” (5) Based on the cooperative control countermeasure of roof–rib–floor surrounding rock, the support technology of roof and ribs supported by blots mesh beam cable + floor supported by bolts grouting hardening + full section shotcrete is proposed. The results of numerical calculation and field test show that the support scheme greatly improves the stability of layered floor.

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“…The regressive models were used as deterministic mathematical models modeled by means of the Monte Carlo method. Li et al [20] analyzed the kinetic interaction of the powered support units with the main roof. They also calculated the dynamic loads of powered support due to the breaking of an overhanging beam.…”

Section: Introductionmentioning

confidence: 99%

A Generalized View of Longwall Emergency Stop Prevention (Ukraine)

et al. 2022

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Based on both theoretical and practical experiences, the measures aimed at controlling emergency shutdowns of stopes have been highlighted. These stopes are connected with the emergency rigid settlements of powered complexes. In terms of the Western Donbas mines, there are certain risks of a shutdown of stopping operations within the zone of primary roof caving. Thus, the causes of emergency rigid settlements of the support may include the following: layers of the main roof rocks are hanging and not timely delaminated; sudden changes in lithology; hydraulic overloading of the main roof; structural flaws of support under certain conditions of its use, etc. In this paper, the theoretical method of scientific cognition was applied, which, with its help, makes it possible to switch from single low-efficiency measures to a set of actions aimed at preventing any uncontrolled situation. Obtaining certain generalized knowledge means obtaining a much deeper representation of reality, penetrating into its essence. The study also involves statistical analysis, being the basis for outlining a zone of primary caving where a high degree of risk is observed. Certainly, the generalization of these measures does not solve the problem completely. Consequently, there will be further attempts to search for and achieve principal new solutions in the future.

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Deformation and fracture at floor area and the correlation with main roof breakage in deep longwall mining

Cited by 16 publications

References 31 publications

Mechanism and Control of Asymmetric Floor Heave in Deep Roadway Disturbed by Roof Fracture

Mechanism and Control of Asymmetric Floor Heave in Deep Roadway Disturbed by Roof Fracture

Study on the effect of rock stratum structure on the stability of weakly cemented layered floor and the floor control measures: A case study of Meihuajing Mine

A Generalized View of Longwall Emergency Stop Prevention (Ukraine)

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