Analysis of Overburden Structure and Pressure‐Relief Effect of Hard Roof Blasting and Cutting

Liu, Hao; Dai, Jianlong; Jiang, Jinquan; Wang, Pu; Ji-qiang, Yang

doi:10.1155/2019/1354652

Cited by 26 publications

(18 citation statements)

References 33 publications

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“…In view of the difference of the abutment pressure at each measuring point between the two stations, we believe that the cutting seam is the main reason for this phenomenon, because the formation of the splitting face can make the roof in the mined-out area collapse more fully, which affects the motion state of the entire coal face roof [26].…”

Section: Overburden Movement Status In Traditional Coal Pillar Miningmentioning

confidence: 99%

An Innovative Technology for Monitoring the Distribution of Abutment Stress in Longwall Mining

Guo

Yin

et al. 2021

Energies

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Fracturing roofs to maintain entry (FRME) is a novel longwall mining method, which has been widely used in China, leading a new mining revolution. In order to research the change law of side abutment pressure and movement law of overlying strata when using the FRME, a new abutment pressure monitoring device, namely, the flexible detection unit (FDU), is developed and is applied in the field. The monitoring results show that compared with the head entry (also called the non-splitting entry), the peak value of the lateral abutment pressure in the tail entry (also termed the splitting entry) is reduced by 17.2% on average, and the fluctuation degree becomes smaller. Then, finite difference software FLAC3D is used to simulate the stress change of the solid coal on both sides of the panel. The simulation results show that the side abutment pressure of the tail entry decreases obviously, which is consistent with the measured results. Comprehensive analysis points out that after splitting and cutting the roof, the fissures can change the motion state of the overlying strata, causing the weight of the overburden borne by the solid coal to reduce; therefore, the side abutment pressure is mitigated.

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Section: Overburden Movement Status In Traditional Coal Pillar Miningmentioning

confidence: 99%

An Innovative Technology for Monitoring the Distribution of Abutment Stress in Longwall Mining

Guo

Yin

et al. 2021

Energies

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“…Great progress has been made in the study of the overlying strata structure and stress field of surrounding rock of RGERC. and [20,21] suggested equations to estimate the roof stress at all stages by considering the evolution process of the overlying short cantilever beam. Through theoretical analysis and field monitoring, He et al (2017) [22] proposed that roof cutting can eliminate the stress connection between the roadway roof and the gob roof so as to weaken the mining-induced pressure and disturbance of roadway surrounding rock.…”

Section: Introductionmentioning

confidence: 99%

Research on the Transmission of Stresses by Roof Cutting near Gob Rocks

Guo

Wang

et al. 2021

Energies

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Pressure relief for roadways retained by roof cutting is essentially caused by stress transfer. In this paper, the stress transfer mechanism of 16011 tail entry with roof cutting in Zhaogu No.1 coal mine is studied from the following two aspects: the change of the tail entry surrounding the rock structure and the interaction between the roadway surrounding rock and supporting structures. It is found by numerical simulation that roof cutting can significantly reduce the magnitude of roadway roof stress, transferring the concentrated stress induced by excavation and mining away from the roadway, and forming an obvious triangle pressure relief area in front of the working face. In the early stage after mining, most of the overburden load is transferred downward through the immediate roof of the roadway. With the movement of overlying strata, the stress, initially transferred to the immediate roof strata, is gradually transferred to the gob, and the calculation formula and influence factors of the transferred stress are derived. In addition, through the establishment of the mechanical model and theoretical calculation of the key rock block of the main roof, the roadside support resistance required to ensure the stability of the main roof block is determined. The field monitoring shows that the lateral pressure coefficient of the roadside caved rocks is 0.36 and the constant resistance and large deformation anchor cable (CRLDAC) and the roadway temporary support play roles of conduction and control in the process of stress transfer, and effectively ensure the stability of surrounding rock during the service life of the retained gob-side entry by roof cutting (RGERC).

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“…Based on the mention above, out in‐depth and detailed numerical studies on the distribution and variation in abutment stress around a stope by incorporating field monitoring, numerical simulation, and theoretical analysis have been carried . For instance, based on the analysis of anchor cable stress monitoring, support resistance monitoring, borehole stress gauge measurement, and microseismic monitoring results, the evolution law of front abutment stress in a working face was studied and summarized . By establishing a two‐dimensional nonlinear numerical model with nonuniform characteristics, a distribution law of front abutment stress was simulated and analyzed .…”

Section: Introductionmentioning

confidence: 99%

“…[15][16][17][18][19] For instance, based on the analysis of anchor cable stress monitoring, support resistance monitoring, borehole stress gauge measurement, and microseismic monitoring results, the evolution law of front abutment stress in a working face was studied and summarized. [20][21][22][23] By establishing a two-dimensional nonlinear numerical model with nonuniform characteristics, a distribution law of front abutment stress was simulated and analyzed. 24 The front abutment stress was deemed to be composed of in situ stress and mining concentrated stress, and the former is a constant pressure, while the latter is caused by a periodic failure of the main roof, which is related to the main roof failure.…”

Section: Introductionmentioning

confidence: 99%

A new theoretical method for calculating front abutment stress during coal mining

Liu

Wang

Liu

et al. 2019

Energy Science & Engineering

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The calculation of abutment stress has always been the most important topic in safe underground mining and design. In this paper, based on the formation mechanism of abutment stress, combined with the mechanical properties of actual strata and the theory of elastic foundation beams, a structure model of overlying strata with an elastic foundation is established, and a new theoretical calculation method of abutment stress is proposed. The new calculation method takes into account the interaction of the overlying key strata and the effect on the transmission of the front abutment stress and then analyzes the stress patterns of multilayered key strata under the combined action of the bending moment, shear force, and nonuniform load and its transmission to the underlying strata. In addition, based on field observations of panel 10 305 in the Xinglongzhuang coalmine, the influence range, peak position, and variation trend of the front abutment stress before and after breaking of the overlying key strata are studied and verified. The results show that the influence range of the abutment stress remains unchanged after KS1 breaks (eg, from 0 to 180 m), and its peak position shifts forward from 8 to 19 m, while the influence range (0‐180 m) and its peak position (6‐8 m in front of coal wall) remain unchanged after KS2 breaks; the abutment stress decreases, and the maximum decrease is 3.9 MPa in the range of 0‐22 m ahead of the coal wall after KS1 breaks, while the maximum decrease in the abutment stress is 2.1 MPa in the range of 0‐71 m ahead of the coal wall after KS2 breaks. The results of the new calculation method are basically consistent with the field observations and the existing theoretical results, showing that the method has good adaptability and reliability and can provide a new theoretical basis for on‐site design and construction practices.

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Analysis of Overburden Structure and Pressure‐Relief Effect of Hard Roof Blasting and Cutting

Cited by 26 publications

References 33 publications

An Innovative Technology for Monitoring the Distribution of Abutment Stress in Longwall Mining

An Innovative Technology for Monitoring the Distribution of Abutment Stress in Longwall Mining

Research on the Transmission of Stresses by Roof Cutting near Gob Rocks

A new theoretical method for calculating front abutment stress during coal mining

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