Mechanism of Roof Shock in Longwall Coal Mining under Surface Gully

Fan, Gangwei; Zhang, Dongsheng; Wang, Xufeng

doi:10.1155/2015/803071

Cited by 12 publications

(9 citation statements)

References 12 publications

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“…Based on multilateral block structure [37][38][39]and mining slope theory [27], when the shallow coal seam is mined through double gullies terrain, the structure and force of the broken block of the gully are shown in Figure 8. With the integral contact between K1 and K2 blocks as the research object, the stress can be analyzed as follows:…”

Section: Discussionmentioning

confidence: 99%

The Development Law of Mining-Induced Surface Cracks in Shallow Coal Seam Through Double Gullies Terrain: A Case Study in a Mine

Sun

Hou

et al. 2021

Preprint

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Mining-induced surface cracks in gullies in shallow seams seriously threaten the development of ecological stability and the safety of mine production. The development law of surface cracks in shallow coal seam mining through double gullies terrain was studied, by taking the Cao Jiatan coal mine in the Yushen Mining Area as a project example. The function T and its discriminant were first put forward to describe the relative position both the surface cracks and working face advanced in shallow coal seam mining through double gullies terrain. The relationship between valley parameters of double gullies terrain and the relative position of surface cracks development was discussed through numerical simulation experiment, similar material simulation experiment and theoretical analysis. The results showed that when the working face passed through the G1 gully, the development of surface cracks led the working face. There were four surface cracks with a maximum width of 23 cm, and the maximum vertical displacement was 11 cm; while passing through the G2 gully, the development of surface cracks lagged the working face. There were seven surface cracks with a maximum width of 79 cm, and the maximum vertical displacement was 45 cm. It can be concluded that the relative position of crack development is greatly affected by geological conditions, gully depth, slope angle, span and other factors of the gully, among of which the gully slope angle is the main influencing factor. T and |T| value has a certain correlation with the lagging distance, crack width, vertical displacement and the total number of cracks in a single gully.

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Section: Discussionmentioning

confidence: 99%

The Development Law of Mining-Induced Surface Cracks in Shallow Coal Seam Through Double Gullies Terrain: A Case Study in a Mine

Sun

Hou

et al. 2021

Preprint

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“…A certain type of shield support was taken as an example in this section. The main parameters of the leg are shown in Table 1 ( Figure 2) and its equivalent stiffness was calculated using (9). It is assumed that is 34 MPa (the active setting force is about 3856 kN).…”

Section: Mathematical Model Of An Equivalent Stiffness Doublymentioning

confidence: 99%

“…It is assumed that is 34 MPa (the active setting force is about 3856 kN). The results obtained by using (9) are shown in Figure 5. Lines OA, AB, and CD represent the stiffness of the leg at stage a, stage b, and stage c, respectively.…”

Section: Mathematical Model Of An Equivalent Stiffness Doublymentioning

confidence: 99%

“…Since the effect of impact loading on coal mining operations is very huge, scholars all over the world have studied the influencing factors of the impact load on the shield support and the decisions behind reasonable shield support capacity. For instance, the authors of [7][8][9] studied the influence of geological conditions on the rock burst tendency using a Finite Element Method. The research reported in [10][11][12][13][14][15] constructed the numerical model of stope and studied the influence of the rock burst on the support load.…”

Section: Introductionmentioning

confidence: 99%

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Analysis on Force Transmission Characteristics of Two‐Legged Shield Support under Impact Loading

Zeng

Meng

Wan

et al. 2018

Shock and Vibration

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To study the load transfer characteristics of a two-legged shield powered support, a numerical simulation model of the support was established using the multibody dynamics software ADAMS. The model took full account of the hydraulic-elastic deformation characteristics of the support, as a series spring-damper system was used to replace the leg and the equilibrium jack. The canopy, goaf shield, lemniscate bars, and equilibrium jack are equivalent to flexible bodies. The setting force of the leg was provided by the preload of the equivalent spring, the static roof load was simulated using a slope signal, and the impact load was simulated using a step signal. Using the model, the impact and excitation effects of each hinge joint of the support were analyzed under different impact load conditions across the canopy. The results show that the location of the impact load affects the force transmissions of all hinge points of the support. Both the impact effect and the excitation effect are at a minimum when the impact force is located near the leg action line. These results are useful for the adaptive control and structural design optimization of the support.

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“…These empirical criteria are also employed in the American coal mining industry, but with some modifications [15,16]. Factors affecting the disturbed zones such as in situ stress [17], physical properties of strata [18][19][20][21], inclination of the coal seam [7,22], and surface topography [12,23] have also been well studied.…”

Section: Introductionmentioning

confidence: 99%

A General Review on Longwall Mining-Induced Fractures in Near-Face Regions

Bai

2019

Geofluids

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It is believed that underground longwall mining usually produces fractures in the surrounding rocks. On the one hand, mining-induced fractures not only degrade the strength of the rock mass but also serve as main channels for fluids (e.g., water and methane). Fractures facilitate the failure of the rock mass and fluid inrush into working spaces. Therefore, mining-induced fractures are significant for the safety evaluation of underground structures and finding feasible solutions. On the other hand, the fractures are also beneficial for methane collection and coal fragmentation, which are essential for the successful operation of longwall top coal caving mining. Therefore, determining the characteristics of induced fractures is significant for underground longwall mining. From a global perspective, longwall mining-induced fractures in the overburden have been well studied, which improves the understanding of the mining pressure and ground control. However, induced fractures near the longwall face, which have more significant effects on mining activities, have not been summarized. The goal of this review paper is to provide a general summary of the current achievements in characterizing mining-induced fractures in near-face regions. The characteristics of mining-induced fractures in the coal wall, chain pillar, immediate roofs and top coal, and floors are reviewed and summarized. Remarks are made on the current progress of, fundamental problems with, and developments in methodologies for characterizing mining-induced fractures using methods such as field observations, small-scale laboratory tests, physical modeling, and numerical modeling. Based on a comprehensive analysis, the advantages and disadvantages of each method are discussed, and the ideal conditions for applying each of these methods are also recommended.

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Mechanism of Roof Shock in Longwall Coal Mining under Surface Gully

Cited by 12 publications

References 12 publications

The Development Law of Mining-Induced Surface Cracks in Shallow Coal Seam Through Double Gullies Terrain: A Case Study in a Mine

The Development Law of Mining-Induced Surface Cracks in Shallow Coal Seam Through Double Gullies Terrain: A Case Study in a Mine

Analysis on Force Transmission Characteristics of Two‐Legged Shield Support under Impact Loading

A General Review on Longwall Mining-Induced Fractures in Near-Face Regions

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