Rock burst mechanism analysis in an advanced segment of gob-side entry under different dip angles of the seam and prevention technology

2019

Self Cite

At present, coal bursts in working faces of steeply inclined coal seams (SICSs) have rarely been investigated, and current research focuses on the influences of roof breaking and instability of overlying structures in goaf on coal bursts; however, the stress state of coal masses in working faces being subjected to coal bursts is rarely researched. To overcome the above defects, a model for analysing stresses on coal masses in horizontal section of SICSs was established based on the coal burst that occurred in LW5521-20, Yaojie No. 3 Coal Mine, Lanzhou, Gansu Province, China. Moreover, the mechanism underpinning such a coal burst in SICSs was analysed based on the superposition mechanism of dynamic and static loads. The results show that the side abutment pressure near the roof and floor under the horizontal sections of SICSs is asymmetrically distributed in the vertical direction in which the peak of side abutment pressure near the roof is closer to the working face and therefore is taken as the source of static loads for coal bursts in working faces. When the superimposed dynamic load caused by hanging roof breaking and high static load borne in the coal masses is larger than the critical load for coal burst inception, a coal burst will occur. Furthermore, the superimposed dynamic load induced by coal bursts on the support and the initial static load on the supports are larger than their limiting load, which leads to support collapse and eventually causes dynamic failure of the working face. The coal burst in working faces in horizontal sections of SICSs can be prevented by using deep-hole presplit blasting in a hard roof, destress blasting in coal masses, and support optimisation of working faces, showing a favourable preventative effect.

Section: Critical Stress Of Coal Burstsmentioning

confidence: 99%

Coal Burst Induced by Horizontal Section Mining of a Steeply Inclined, Extra‐Thick Coal Seam and Its Prevention: A Case Study from Yaojie No. 3 Coal Mine, China

2019

Self Cite

“…In recent years, with improvement and development of microseismic monitoring system, researchers deduced and analyzed fracture and movement law of thick and hard strata according to collecting microseismic data in engineering practices and carried out lot of conclusions [20][21][22]. Numerous other scholars have conducted a lot of exploration and research work on the mechanism and law of mining earthquakes activity of thick and hard strata based on various points and view [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Study on Characteristics of Mining Earthquake in Multicoal Seam Mining under Thick and Hard Strata in High Position

Zhu

Zhang

et al. 2021

Rock burst has become one of the most serious world’s problems in coal resources mining, and fracture and movement of thick and hard strata in high position is the main reason to induce strong mining earthquake and rock burst. Multicoal seam mining of 10302 working face in Baodian coal mine is selected as an engineering background, which has thick and hard strata in high position. Using SOS microseismic monitoring system to collect microseismic events and date during multicoal seam mining, characteristic and difference of microseismic in multicoal seam mining under thick and hard rock in high position is analyzed systematically. The main research work is as follows: reveal temporal and spatial distribution and evolution law of microseismic and analyze difference and correlation of microseismic in multicoal mining under thick and hard strata in high position, especially the relationship between mining earthquake with high energy and fracture and movement of thick and hard strata in high position. With the characteristics of microseismic, rock burst mechanism and difference induced by thick and hard strata in high position are discussed. The research and achievement could make guidance to multicoal seam mining safety under thick and hard strata in high position.

“…In recent years, with the popularity of fully mechanized mining hydraulic support and the improvement of supporting strength of working face, rock burst accidents appear mostly in the roadway. Research statistics showed that more than 75% of rock burst accidents occurred in the two tunnels of the working face, especially in the advance support range of 0∼80 m of the working face [1][2][3]. erefore, the research of antierosion of roadway with rock burst has become one of the important issues to be solved urgently.…”

Section: Introductionmentioning

confidence: 99%

Study on Occurrence Mechanism of Coal Pillar in L‐Shaped Zone during Fully Mechanized Mining Period and Prevention Technology

Yang

Sun

et al. 2021

In order to study the occurrence mechanism of rock burst in L-shaped zone during a fully mechanized mining period, the No. 705 working face which is located in Baojishan Colliery is taken as a typical engineering background. By means of in situ investigation, theoretical analysis, numerical simulation, in situ tests, and relevant monitoring methods, the occurrence mechanism of rock burst and corresponding prevention technology are studied. The results show that a coal pillar with some confining pressure in the L-shaped zone is established by FLAC3D numerical simulation software, and the numerical simulation results indicate that the change in static load has a greater effect than dynamic load on coal pillar unstable failure; the static load plays a role in storing energy, and dynamic load plays a role in inducing rock burst; the bolt-mesh-cable support and high-pressure water jet unloading combined technology is put forward to prevent rock burst in roadways, and the numerical simulation results show that stress distribution of surrounding rock meets the model of strong-soft-strong (3S) structure, and the moment distribution is reasonable. In the follow-up mining, a limit value of coal fines is used to determine that this measure is a reasonable method to prevent rock burst. The study conclusions provide theoretical foundation and new guidance for preventing rock burst by synergistic effect technology in roadways.