Stress environment around head entries with pillarless gobside entry retaining through numerical simulation incorporating the two type of filling wall

Sakhno, Ivan; Sakhno, Svitlana; Kamenets, V I

doi:10.1088/1755-1315/1049/1/012011

Cited by 10 publications

(8 citation statements)

References 24 publications

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“…Backfilling in Ukraine is carried out mainly for the conditions of ore deposits [37,38]. The theoretical studies are also carried out for coal deposits [39][40][41]. The presented study is planned to develop in this direction.…”

Section: Resultsmentioning

confidence: 99%

Numerical simulation of the surface subsidence evolution caused by the flooding of the longwall goaf during excavation of thin coal seams

Sakhno,

Petrenko

et al. 2023

IOP Conf. Ser.: Earth Environ. Sci.

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Underground mining has a significant influence on ground movement, which induces serious environmental disturbances on land. Movements of the rock strata can be the cause of changes in the hydrogeological regimes of groundwater. As a result, the risk of flooding of the longwalls goaf increases. The specific phenomenon of the Ukrainian Donbas is the flooding of the underground roadway system at the result of the closure of the mines. Water saturation of rocks leads to a decrease in its strength. The result is repeated subsidence. The activation of the ground movement processes over the longwall goaf due to their flooding has not been studied enough. In this paper, for the geological conditions of thin coal seams typical for the Ukrainian Donbas, ground movement evolution caused by flooding of longwalls goaf was studied. Ansys code was used to analyze the evolution of surface displacement in different hydrogeological conditions. As a result of numerical simulation, it was found that full flooding of the longwall goaf leads to an increase in surface subsidence by 22.4%, while the length of the trough increase by 1.3%. Maximal inclination increases by 34.4%, and maximal curvature – by 74%. This contributes to a significant increase in hazards for surface infrastructure located on the edges of the subsidence trough. The control of the negative impact on surface infrastructure objects, water and agro-industrial objects can be ensured by a timely prediction of ground movement and the implementation of surface controlling methods to prevent critical surface deformations.

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Section: Resultsmentioning

confidence: 99%

Numerical simulation of the surface subsidence evolution caused by the flooding of the longwall goaf during excavation of thin coal seams

Sakhno,

Petrenko

et al. 2023

IOP Conf. Ser.: Earth Environ. Sci.

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“…Sakhno et al 8 studied the stress distribution and displacement variation of the main roof for gob‐side entry in the working behind the longwall face. Sakhno et al 9 studied the stress field evolution around head entries with gob‐side entry retained through numerical simulation with two variants of filling wall. Frith et al 10 explored the limitations of empirically derived coal pillar strength equations and proposed a modified coal pillar design representation and model based on coal pillars acting to reinforce a horizontally stressed overburden.…”

Section: Introductionmentioning

confidence: 99%

Research on deformation characteristics and control technology of surrounding rock for gob‐side entry with small coal pillar in gently inclined coal seam

Wang,

Zhou,

Zhang

2024

Energy Science & Engineering

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With the engineering background of the gob‐side entry of panel SA1104 in Heiyanquan Coal Mine, the deformation characteristics and control technology of the surrounding rock for gob‐side entry with small pillar in gently inclined coal seam have been studied by field observation, numerical simulation, and theoretical analysis. The study show that: (1) The surrounding rock has obvious asymmetric deformation characteristics, the roof subsidence on the solid coal side is larger than that on the small coal pillar side; the deformation of small coal pillar side rib is more significant than that of the solid coal side rib, which is concentrated in the middle and upper part, and slip deformation occurs at the upper sharp corner; the middle part of solid coal side rib exhibits prominent deformation; and floor heave is shifted to the small coal pillar side. (2) The stress concentration zone on the small coal pillar side is located 1.9 m from the high rib, while the stress concentration zone on the solid coal side is located 4.1 m from the low rib. The difference in the rib‐to‐rib peak stress is 4.2 MPa, and the stress concentration on the solid coal side is larger than that on the small coal pillar side. (3) Poor physical and mechanical properties of the surrounding rock, high in‐situ stress, and high deterioration degree of the surrounding rock structure are the main internal causes of the entry deformation; strong mining disturbance, arbitrary support parameters, and large section sizes are the main external causes of the entry deformation. (4) The asymmetric combined support program is proposed, featuring “non‐equidistant cable + inclined bolt on the roof, bolt extension + cable supplement on the small coal pillar side rib, and bolt encryption on the solid coal side rib”, and it had a positive on‐site application effect.

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“…The caving rock mass forms a support structure for the overlying basic roof rock beam, which controls the rotary sinking deformation of the main roof. At the same time, the roof cutting forms the roadway side to cut off the goaf, automatically forms the roadway to be used for the next working face mining, and finally realizes that a working face only needs to excavate one roadway, which means that a mining working face only needs to excavate one roadway, leaving zero coal pillar mining modes [13][14][15][16][17][18]. Implementing the 110 mining method minimizes roadway excavation, mitigates the risk of rock bursts, and significantly enhances the coal resource recovery rate.…”

Section: Introductionmentioning

confidence: 99%

Mitigating Coal Spontaneous Combustion Risk within Goaf of Gob-Side Entry Retaining by Roof Cutting: Investigation of Air Leakage Characteristics and Effective Plugging Techniques

Zhang,

Chen,

et al. 2024

Fire

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Relative to conventional coal pillar retention mining technology (the 121 mining method), gob-side entry retaining by cutting roof (the 110 mining method), a non-pillar mining technique, efficiently addresses issues like poor coal resource recovery and significant rock burst damage. Nonetheless, the open-type goaf created by 110 mining techniques suffers from complex and significant air leaks, increasing the likelihood of coal spontaneous combustion (CSC) within the gob area. To address the CSC problem caused by complex air leakage within the goaf of gob-side entry retaining by roof cutting, this study takes the 17202 working face of Dongrong Second Coal Mine as the object of study. Field tests and simulation calculations are conducted to research the features of air leakage and the distribution of the oxidation zone within the goaf. Subsequently, plugging technology with varying plugging lengths is proposed and implemented. The tests and simulations reveal that the airflow migration within the goaf follows an L-shaped pattern, while air leakage primarily originates from gaps found in the gob-side entry retaining wall. The amount of air leaking into the gob-side entry retaining section is 171.59 m3/min, which represents 7.3% of the overall airflow. The maximum oxidation zone within the goaf ranges from 58.7 m to 151.8 m. After the air leakage is blocked, the airflow migration route within the goaf is transformed into a U-shaped distribution, and the maximum oxidation zone range changes from 42.8 m to 80.7 m. Engineering practice demonstrates that after air leakage plugging, the total air leakage volume within the gob-side entry retaining section significantly reduces to 20.59 m3/min, representing only 0.78% of the total airflow volume. This research provides reference on how to prevent the occurrence of CSC in similar mine goafs.

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Stress environment around head entries with pillarless gobside entry retaining through numerical simulation incorporating the two type of filling wall

Cited by 10 publications

References 24 publications

Numerical simulation of the surface subsidence evolution caused by the flooding of the longwall goaf during excavation of thin coal seams

Numerical simulation of the surface subsidence evolution caused by the flooding of the longwall goaf during excavation of thin coal seams

Research on deformation characteristics and control technology of surrounding rock for gob‐side entry with small coal pillar in gently inclined coal seam

Mitigating Coal Spontaneous Combustion Risk within Goaf of Gob-Side Entry Retaining by Roof Cutting: Investigation of Air Leakage Characteristics and Effective Plugging Techniques

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