Local reinforcing of footing supported in the destroyed rock massif

Sakhno, Ivan; Isayenkov, O; Rodzin, S

doi:10.15407/mining11.01.009

Cited by 12 publications

(10 citation statements)

References 5 publications

(5 reference statements)

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“…Floor restoration was carried out with a Hasemag EL160 loader machine to ensure the required cross-sectional area in the gob-side entry retaining. This practice is typical for coal mines in Ukraine [41]. Scholars from other countries report similar cases of critical floor heave [16,18,27,42,43].…”

Section: Supporting Parameters and Deformation Of Gob-side Entry Reta...mentioning

confidence: 68%

Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology

Sakhno,

Skrzypkowski

et al. 2024

Applied Sciences

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The severe floor heave in gob-side entry retaining is the major restriction factor of the wide application of pillarless mining thin coal seams. Reinforcement and stress-relief floor heave control methods are the most promising. However, in practice, floor restoration is widely used. Therefore, floor heave control technology in gob-side entry retaining needs to be improved. This study proposes anti-shear pile technology to control floor heave in gob-side entry retaining. The research was mainly carried out by numerical simulation. It was found that the transformation of high vertical stresses in the entry floor underneath the filling wall and coal seam body into horizontal stresses starts the floor heave process. The vertical dilatancy of rocks under the roadway span and their subsequent unloading lead to the delamination of the floor strata and uplift of the entry contour. In this paper, the best pile installation scheme was found. It is a 2pile 5+2 scheme with the installation of two piles, each 2 m long. After that, it was shown that filling piles are more than 3.3 times cheaper than comparable analogs, and pile installation is less labor-intensive. The implementation of the proposed floor heave control method leads to a reduction in heaving by 2.47 times.

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Section: Supporting Parameters and Deformation Of Gob-side Entry Reta...mentioning

confidence: 68%

Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology

Sakhno,

Skrzypkowski

et al. 2024

Applied Sciences

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“…Laboratory studies, the results of which are presented in [7], prove that the formation of locally strengthened zones of a special shape in a mass, represented by a discrete medium, makes it possible to reduce the compaction of rocks under the mine roadway by 20% and the heaving of floor rocks by at least 40%. Based on the results obtained during the research, a working hypothesis has been formulated to ensure the stability of the floor by creating locally strengthened zones, which is given below.…”

Section: The Idea Formation Of a Methods For Controlling The Floor Heavementioning

confidence: 98%

“…These data have been obtained for mines with one or two longwall faces. For roadways serving the stope face, 90% of the deformations are associated with being in the zone of longwall face impact, while about 86% of the repair work is accompanied by dinting of the floor rocks [7].…”

Section: Introductionmentioning

confidence: 99%

Method for controlling the floor heave in mine roadways of underground coal mines

Sakhno¹,

Liashok²,

Isaienkov³

et al. 2022

Min. miner. depos.

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The method development and research on controlling the floor heave of mine roadways located in the zone of increased stresses by local strengthening the rocks with mixtures expanding in the solid phase.Methods. The work uses the following research methods: analysis and generalization of previously performed research on the process of heaving the floor in mine roadways; full-scale mining studies, which include instrumental measurements at benchmark stations, rapid measurements, photo-fixation of floor rock cuts in the areas of dinting.Findings. It has been determined that the problem of heaving the floor is relevant for most of the temporary roadways located in the zones of increased stresses, for example, in the zone of longwall face impact, both Ukrainian and foreign coal mines. The conducted full-scale mining studies have revealed that the floor rocks in the zone of increased stresses are in a destroyed state and can be represented as a block-discrete medium. A method for controlling the floor heave in mine roadways has been developed, which is based on the formation of locally strengthened zones of a special shape in the mine roadway floor. The strengthening effect is achieved by consolidating the rocks due to their compression by mixtures expanding in the boreholes drilled into the floor of the mine roadway. The method parameters have been calculated which make it possible to set the necessary expansion pressures for the formation in the mine roadway floor of a stable strengthened zone of a specified shape. Studies on the formation of local strengthening of floor rocks with mixtures expanding in mine conditions substantiate the fundamental possibility of rock consolidation.Originality. The ideas about the consolidation of a block-discrete medium by compression and the formation of stable strengthened zones with mixtures expanding in the solid phase have been developed.Practical implications. A method for controlling the heaving of floor rocks and a methodology for determining the method parameters have been developed. The results obtained can be used to ensure the stability of mine roadways in zones of increased stresses.

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“…Te foor heave on stations, which were built in roadways D-2 and F-33b, was monitored over two years [30]. In roadway D-2, the maximum value of upheaval after almost 800 days of monitoring was 0.54 m, and in roadway F-33b 0.6 m. Te average value of foor heave on monitoring stations in the conveyor roadway of 5 longwalls of 3 m seam was 0.7 m [31]. Te zone of rock cracking in the foor of the roadway was more than 7 m. Te foor heave of the roadway of the Qitaihe Longhu coal mine [27] was very serious; the maximum foor heave was 0.9 m, which seriously restricted the efcient production of the coal mine.…”

Section: Supporting System and Deformation Characteristicsmentioning

confidence: 99%

Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

Sakhno

2023

Advances in Civil Engineering

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The floor heave is one of the key factors that can restrict high-efficiency and safety mining, especially in the deep roadways with soft rock. Considering the influences of rock fracturing over time on rock mass properties, a case study of the floor heave evolution and rock bolts reinforcement technology was performed in this paper. A numerical simulation was used to study the stress-strain state and displacement of surrounding rocks. It was found that significant floor heave caused by nonlinear deformation of laminated immediate floor under an increase in rock fracturing. The post-peak strain regions appear in the bottom corners of the roadway, after which strata in the immediate floor are destroyed one by one. The joint spacing of 0.45 m on the immediate floor is critical. At this step, post-peak strain regions merge in the central part of the roadway floor, which is the cause of uncontrolled floor heave. Rock bolts reinforcement was proposed to control the floor heave. Three floor support schemes with two types of support elements, different bolt orientations, and lengths of reinforcement were studied. The numerical simulation demonstrated that after reinforcement, post-peak plastic strain in the floor strata was reduced effectively. The optimal floor support scheme and depth of reinforcement were determined by the allowable floor heave. Ideally, the floor heaves could be reduced by rock bolts with a steel belt installed according to the support scheme III and reinforcement length of 2.0 m for outer bolts and 3.0 m for central bolts.

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Local reinforcing of footing supported in the destroyed rock massif

Cited by 12 publications

References 5 publications

Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology

Floor Heave Control in Gob-Side Entry Retaining by Pillarless Coal Mining with Anti-Shear Pile Technology

Method for controlling the floor heave in mine roadways of underground coal mines

Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

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