Longwall mining method with roof-cutting unloading and numerical investigation of ground pressure and roof stability

Li, Zhaohua; Tao, Zhigang; Meng, Zhigang; He, Manchao

doi:10.1007/s12517-018-3962-z

Cited by 19 publications

(8 citation statements)

References 18 publications

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“…Under static load, the vertical earth pressure of A-A section was U-shaped symmetrical distribution, with the creep of the fill, the vertical earth pressure of A-A section increased to the size of the theoretical earth pressure; under seismic action, the distribution of vertical earth pressure is similar to the static earth pressure, but the earth pressure value has increased and the increase of the vertical earth pressure on the left side of the roof of the cave is smaller than the right side. Equivalent load method [18] Calculated by "equivalent load method [18] ", the average vertical earth pressure on the left side (right side) of the cave roof under seismic action is 1.12~1.05~1.02 times (1.15~1.06~1.02 times) of that under static loading at different time periods after the completion of filling. It can be seen that the increase of vertical earth pressure on both sides of the roof of the cave is getting smaller in different time periods after the completion of filling, and the change of earth pressure under seismic action is the largest in 0 years after the completion of filling.…”

Section: Vertical Earth Pressurementioning

confidence: 99%

Seismic Effect Analysis of High-Filled Cuter Cover Tunnel Considering the Time-dependent Nature of Fill Soil

Shi,

Li,

et al. 2024

Atlantis Highlights in Engineering

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In order to investigate the seismic effect analysis of High-Filled Cuter Cover Tunnel based on equal load reduction rate and considering the timeliness of filling, three load-reducing materials, namely, EPS board, low-pressure solid soil and rubber granular improved soil, are selected, and the effects of the differences in load-reducing materials on the soil pressure around the caves and the safety of the lining are analyzed under the effect of earthquakes, using a combination of experiments and numerical simulations. The results show that: under seismic action, the average vertical dynamic soil pressure on the left side of the cave roof is 1.12~1.05~1.02 times of the static loaded soil pressure, and the dynamic soil pressure on the right side is 1.02~1.01~1 times of that on the left side; the horizontal dynamic soil pressure on the left and right sides of the cave shows a trend of "this is the opposite of the other", and the average horizontal dynamic soil pressure on the left side of the cave is 0.5~2 times of that on the right side. The average horizontal dynamic soil pressure on the left side (right side) of the hole is 0.63~0.88~1.03 times (1.95~1.32~1.08 times) of the static load soil pressure. The distribution of structural safety coefficient tends to be symmetrical from asymmetric in order, and the smallest part of the safety coefficient is transferred from the arch top to the right side wall. When seismic design is carried out in High-Filled Cuter Cover Tunnel, attention should be paid to the safety performance of the lining structure arch top and right side wall.

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Section: Vertical Earth Pressurementioning

confidence: 99%

Seismic Effect Analysis of High-Filled Cuter Cover Tunnel Considering the Time-dependent Nature of Fill Soil

Shi,

Li,

et al. 2024

Atlantis Highlights in Engineering

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“…Figure 1 illustrates the working face's layout. According to insufficient statistics, there are 7 billion tons of remaining space pillar resources in Ordos City, Inner Mongolia, and the remaining space pillar resources in Shaanxi province's Shen mu County amount to about 2 billion tons 6,7 . Based on the mining technology of cutting roofs and relieving pressure without coal pillars, 8 He Mancha, an academician, proposed the technology of cutting roofs and relieving pressure without coal pillars 9,10 to increase resource recovery rates.…”

Section: Introductionmentioning

confidence: 99%

Evolution law and application of permeability in gob without coal pillar and self‐formed roadway

Liu

Feng

2022

Energy Science & Engineering

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Roof-cutting and pressure-releasing technology are used to cut out the pressure transmission line of the critical blocks in the roof, causing the roof to totally collapse in the gob, while the NPR large deformation anchor cable support keeps the highway in its self-formed state. The gangue compactness has increased greatly when fully collapsed and filled to the gob's edge. At the end of the working face, the void ratio between rock blocks and the loose area is decreased, resulting in an observable shortening of the airflow disturbance distance at the working face and a change in the disaster gas accumulation law in the deep gob. It is critical to obtain the permeability characteristics of gob to avoid hazardous gas migration. The evolutionary model of the permeability of the mined-out region is created based on the analysis of the movement law of the overburden strata and the collapsed law of the gangue in the gob, and the "Z" ventilation model is built to research the airflow law in the gob. The following are the key conclusions reached: The 0-10 m airflow exchange zone is severe, the 10-45 m airflow return face is weak, the 45-190 m section airflow exchange is weak, and the 190-280 m section airflow confluence gob enhances the top corner's weak air area. The 0-50 m part of the self-formed Roadway has a wide air leakage channel, and good sealing methods have a significant impact on air leakage in the working face. The two-dimensional model constructed by comprehensive quantification of the main controlling factors, such as broken-expand, pressure, and filling degree, can represent the law of gas migration in the panel to a significant extent, and the reliability of the permeability evolution law is confirmed through data comparison and analysis.

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“…For example, certain in-depth studies should be explored as to the stability mechanism of the entry roof formed by roof cutting, the stress distribution characteristics of the surrounding rock, the law of the roof deformation variation, and the appropriate control countermeasures. To date, many findings for these problems have been reported [13][14][15]. However, the existing research results are all aimed at the stage of retaining roadway.…”

Section: Introductionmentioning

confidence: 99%

Mine Pressure Behavior Characteristics and Control Methods of a Reused Entry that Was Formed by Roof Cutting: A Case Study

Wang

et al. 2020

Shock and Vibration

Self Cite

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Noncoal pillar mining with automatic formation of a roadway is a new coal mining method that is tailored to improve the coal resource recovery rate and reduce the investment in roadway tunneling. Using this proposed method, a reuse entry is formed by roof cutting instead of tunneling. In this paper, the S1201-II working face of the Ningtiaota Coal Mine was used as a case study. The stress distribution of surrounding rock and the roof deformation characteristics of the reused entry during the mining process of the second working face were studied through FLAC3D numerical simulations combined with field measurements. The results indicate that the zone close to the reused entry led to higher stress in advance. If this stress is superimposed with the lateral pressure of the adjacent mined working face, it will be more difficult to maintain the reused entry. In the engineering case study described here, the reused entry created a stress increase zone and a severe deformation zone in the range of 0–80 m in front of the working face, and its range was approximately 37.5% larger than an ordinary entry. The stress peak in the stress increase zone increased by approximately 34.7% over that of an ordinary entry. The maximum amount of deformation within the severe deformation zone increased by 94.4% over that of an ordinary entry. To properly control the surrounding rock stress and deformation of the reused entry, a dynamic pressure bearing support in front of the working face with adaptability to the large roof deformation and high support strength is proposed here. Field application results showed that the final roof deformation with the dynamic pressure bearing support can be satisfactorily controlled within 110∼130 mm. These findings can provide a reference for researchers and field engineering technicians when engaging in the support work of reused entry.

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Longwall mining method with roof-cutting unloading and numerical investigation of ground pressure and roof stability

Cited by 19 publications

References 18 publications

Seismic Effect Analysis of High-Filled Cuter Cover Tunnel Considering the Time-dependent Nature of Fill Soil

Seismic Effect Analysis of High-Filled Cuter Cover Tunnel Considering the Time-dependent Nature of Fill Soil

Evolution law and application of permeability in gob without coal pillar and self‐formed roadway

Mine Pressure Behavior Characteristics and Control Methods of a Reused Entry that Was Formed by Roof Cutting: A Case Study

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