Application of High‐Strength Lightweight Concrete in Gob‐Side Entry Retaining in Inclined Coal Seam

Zhu, Daoyong; Gong, Weili; Su, Yi; Guo, Aipeng

doi:10.1155/2020/8167038

Cited by 2 publications

(2 citation statements)

References 19 publications

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“…Gob-side entry retention (GER), as an important technique in coal mining system without pillars [1][2][3][4], can improve the recovery rate of coal resources, reduce the rate of tunnelling of roadways, and avoid the waste of resources [5], owing to which it has been widely used in various coal mines in countries such as China, Germany, Poland, and the United Kingdom and has achieved remarkable economic and social benefits [6]. As a conventional material for roadway sidewall supporting, concrete blocks are characterised by large support resistance in the early stage, large rate of increase in resistance, favorable roof-cutting effect, and favorable sealing effect of the goaf.…”

Section: Introductionmentioning

confidence: 99%

Innovative Control Technique for the Floor Heave in Goaf-Side Entry Retaining Based on Pressure Relief by Roof Cutting

Wang

et al. 2021

Mathematical Problems in Engineering

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To solve the difficulty in controlling floor heave of a retained goaf-side roadway, a new control technique was investigated from the perspective of the pressure relief by roof cutting by combining mechanical analysis, numerical simulation, and engineering tests. The mechanical principle of controlling the floor heave based on pressure relief by roof cutting was attained by analyzing the movement of overlying strata and mechanical characteristics of key blocks before and after the roof cutting. A new technique for controlling the floor heave based on pressure relief by roof cutting was proposed. Research results have shown that after performing pressure relief by roof cutting, the caved gangues in the goaf can support the overlying strata and, thereby, change the movement law thereof and weaken the abutment pressure on the coal wall. Furthermore, the pressure exerted on the roadway floor by the coal wall is lowered to prevent plastic deformation of the floor, thus controlling floor heave in the roadway; a new integrated technique for controlling the floor heave based on pressure relief by roof cutting, flexible yielding, controlling with double-direction-control anchor bolts, and controlling with reinforcing anchor cables is developed, and the technological processes of support, cutting, and protection are summarised. The results of field testing showed that, after applying the new technique, the average floor heave amount of the roadway declines by 64% and the average speed of the floor heave up to 231 m behind the working face decreases by 61%.

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Section: Introductionmentioning

confidence: 99%

Innovative Control Technique for the Floor Heave in Goaf-Side Entry Retaining Based on Pressure Relief by Roof Cutting

Wang

et al. 2021

Mathematical Problems in Engineering

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“…On this basis, the control principle of roadways was proposed-reasonable selection of the width of the coal pillar, supported with a high strength and large elongation anchor, and using a pair of anchor cables and grouting to strengthen the narrow coal pillar [15][16][17][18]. Liu et al confirmed the determination of the reasonable width of the isolated coal pillar is the key to ensure safe mining in the deep coal seam with goaf, which is concluded as follows: (1) The evolution of the overburden space structure during mining in the goaf area is a "fixed S-type, mobile S-type, conjoined S-type, C-type, and U-type", and the stress evolution process of the isolated coal pillar is "fixed support pressure, mobile support pressure, stress superimposition, coal pillar stress concentration"; (2) Causes of goaf-induced rockburst induced by mining is that the stress of the coal body reaches the impact stress condition; (3) Under the condition of high-pressure relief around the isolated coal pillars, it was determined that the reasonable width of the isolated coal pillars was 65 m, and good results were obtained through practice [19][20][21]. Wang et al studied the deformation law and control technology of a goaf-side entry driving heading mining face, obtained that the surrounding rock exhibits asymmetric deformation, and that the narrow coal pillar and roof are severely deformed after being affected by the mining of adjacent mining faces, and put forward that improving the support strength of the narrow coal pillar and roof to form an effective bearing body is the key to maintaining the overall stability of the goaf-side entry driving heading mining face.…”

Section: Introductionmentioning

confidence: 99%

Control of the Surrounding Rock of a Goaf-Side Entry Driving Heading Mining Face

Bai

Wang

et al. 2020

Sustainability

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Different from the traditional goaf-side entry in the mining face, a goaf-side entry driving heading mining face can greatly alleviate the problem of mining and excavation replacement tension under the high-intensity mining condition of a single-wing mine, withstanding the whole process of the fracture, rotation, and sinking of key blocks in the overlying rock layer, which is extremely difficult to maintain. Taking the roadway layout in a single-wing mining face of a coal mine in Neimenggu, China as the research background, first, the stress environment and structural stability characteristics of a goaf-side entry driving heading mining face is qualitatively analyzed with the theoretical analysis method according to five different stages. Secondly, the distribution and evolution law of stress and displacement with a goaf-side entry driving heading mining face are systematically studied during the whole process of advanced mining, excavation, and mining with the numerical simulation method, and the reasonable width of the section of the coal pillar is determined to be 6.0 m. Finally, the deformation laws of a goaf-side entry driving heading mining face are revealed with the field survey method: (1) the stage of advanced mining—the function relation between the distance of the excavation and mining face and roadway displacement is approximately the logistic function; (2) the stage of goaf-side entry driving—the function relation between roadway displacement and the driving distance basically forms the exponential function. Based on the above research, the dynamic segmentation control principle of “high-resistance support, dynamic monitoring, sectional control, consolidation coal sides, and stable roof control” and the dynamic segmentation control technology of “section combined strong support of anchor, net, cable, and beam, narrow coal pillar grouting and reinforcement in key periods, strengthening support of the roof with a single pillar π steel beam”, and industrial tests are carried out on site. The monitoring results of the underground pressure show that the deformation failure of the goaf-side entry driving heading mining face is effectively controlled with the control principle and technology, the difficult problem of mining and excavation replacement tension is alleviated with the single-wing mine, and the useful reference and reference for the engineering practice under similar conditions are provided.

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Application of High‐Strength Lightweight Concrete in Gob‐Side Entry Retaining in Inclined Coal Seam

Cited by 2 publications

References 19 publications

Innovative Control Technique for the Floor Heave in Goaf-Side Entry Retaining Based on Pressure Relief by Roof Cutting

Innovative Control Technique for the Floor Heave in Goaf-Side Entry Retaining Based on Pressure Relief by Roof Cutting

Control of the Surrounding Rock of a Goaf-Side Entry Driving Heading Mining Face

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