Experimental Research on Dynamic Evolution Characteristics of Roof Movement and Mining-Induced Stress of Superimposed Mining in a Close Distance Coal Seam Group

Cheng, Zhiheng; Ma, Haifeng; Sang, Cong; Liu, Yanqing

doi:10.1007/s10706-019-00968-0

Cited by 23 publications

(22 citation statements)

References 4 publications

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“…For example, the numerical simulation of the close coal seams group in Wanli mining area shows that the height of water-conducting fracture zone in overlying strata increases slightly after the mining of lower coal seam (Huang et al 2012); aiming at the mining conditions of the close coal seam group, the evolution characteristics of stress-fracture distribution in surrounding rock under the influence of double mining of protective layer and protected layer are expounded. It is found that after dual pressure relief mining, the scope and degree of pressure relief of surrounding rocks increase slightly (Cheng et al 2016); the differences between deep mining and shallow mining are summarized and the deformation, strength and failure characteristics of deep rock mass are given. It is pointed out that deep rock is in a complex mechanical environment of ''three high and one disturbance'' (He et al 2005); the pressure rod mechanical model of coal face is established to analyze coal face stability.…”

Section: Introductionmentioning

confidence: 99%

The Roof Breaking Characteristics and Overlying Strata Migration Law in Close Seams Group Under Repeated Mining

et al. 2019

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In view of the fact that the roof breaking characteristics and overlying strata migration law of close coal seams under repeated mining conditions are not clear, which seriously affects the safety advancing of working face. A large-cutting-height panel in Panjiang of Guizhou Province is used as an example, the roof breaking characteristics and overlying strata migration law under repeated mining are studied using theoretical analysis, numerical simulation and field observation. The research results show that although the roof weighting is not strong in close coal seams mining, there are three kinds of roof weighting phenomena frequently in different overlying strata stratum and the coal face is easy to failure due to the repeated mining; the theoretical formula (5) for determining the support resistance is obtained by establishing the mechanical model and the calculated support resistance of 7200 kN can be determined; compared with the single coal seam mining, the initial weighting interval is smaller and the periodic weighting interval will not change much under the repeated mining; after theoretical analysis and numerical simulation, it can be known that it is necessary to strengthen the control of coal face stability and prevent safety accidents caused by coal face rib spalling in close seams group under repeated mining. The research results provide a theoretical basis for coal seam mining under similar conditions.

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Section: Introductionmentioning

confidence: 99%

The Roof Breaking Characteristics and Overlying Strata Migration Law in Close Seams Group Under Repeated Mining

et al. 2019

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“…FLAC 3D , RFPA 2D , UDEC, and other software are widely used in stope simulation [12][13][14][15]. Two-dimensional and three-dimensional indoor similar tests can assess the stope conditions reliably reducing the research cost [16][17][18][19]. A mechanical model under different geological conditions can better reveal the mechanism of overlying strata migration and fracture in the mining process of close coal seam [20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Study on Evolution Characteristics of Regenerated Roof Structure in Downward Mining of Bifurcated Coal Seam

Shi

et al. 2021

Advances in Materials Science and Engineering

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In recent years, the structural evolution characteristics of the regenerated roof of the lower coal seam have become a research hotspot when the bifurcation coal seam is mined downward. In this paper, taking the bifurcation coal seam of Xutuan Coal Mine in China as an example, the structural evolution characteristics of regenerated roof under the influence of mining in bifurcation coal seam are comprehensively studied by theoretical analysis, field measurement, and indoor similar simulation experiment. The stress transfer law in the floor after mining in the upper coal seam is also analyzed. The results show the overburden structure and stress field change caused by upper coal seam mining. The caving and fracture zones are formed in the roof, the average height of the caving zone is 8.28 m, and the one of the fracture zone is 34.91 m. The results of the field test verify the accuracy of theoretical analysis and similar simulation test results. According to the relative size of the depth of the strong failure zone of the coal seam floor and the coal seam spacing, the rock mass structure of the regenerated roof of lower coal seam is divided into three types: fractured rock mass + scattered rock mass (I), fractured rock mass + scattered rock mass + fractured rock mass (II), and fractured rock mass + bulk rock mass + fractured rock mass + layered rock mass (III), and the stability of the three types of regenerated roof structure is evaluated: III > II > I. The research in this paper can provide a theoretical basis for determining the target area of broken roof control under the mining conditions of bifurcation coal seam and provide guidance for the selection of the location and parameters of the grouting borehole for roof reinforcement.

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“…Compared with mining in a single coal seam, a closely spaced coal seam is more severely affected by the mining of the upper seam and the mining of the adjacent working face, which results in a very complicated spatial structure of, and stress environment in, the rock surrounding the roadway. e roadway dynamic pressure is significant and more prone to roof leakage and other accidents in the process of roadway excavation and working surface recovery [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Optimal Layout of the Roadway in Closely Spaced Ultra‐Thick Coal Seams Mining with Remaining Coal Pillars

Gao

Tian

et al. 2021

Shock and Vibration

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The reasonable layout of the roadway in closely spaced, ultra-thick coal seam mining is of great significance to mining safety. Based on the research background of repeated roof leaks in the process of repairing the return air roadway in working face No. 30503 in the Tashan Coal Mine, theoretical analysis, in situ engineering testing, and numerical simulation were jointly adopted to evaluate the stability of the return air roadway under two schemes of repairing the original return air roadway and excavating a new return air roadway. The results show that the vertical mining-induced fissure above the roadway will cause severe damage to the roadway due to the influence of working-face mining when restoration of the roadway excavation is adopted. When choosing to excavate a new return air roadway, the new return air roadway just staggers the vertical cracks located in the top slab of the original return air roadway, putting the roadway in a state of stress reduction, making the roadway itself more stable and conducive to support. Therefore, the new air return tunnel was selected to establish the working face. To ensure safety of the working face during the mining of the original return air roadway, the original return air roadway was filled with high water content materials. Site investigation data show that this material plays a cushioning role in the filling section of the original return air roadway during the mining of the 30503 working face, and the deformation of the new return air roadway during the filling section crossing the original return roadway is stable and well controlled.

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Experimental Research on Dynamic Evolution Characteristics of Roof Movement and Mining-Induced Stress of Superimposed Mining in a Close Distance Coal Seam Group

Cited by 23 publications

References 4 publications

The Roof Breaking Characteristics and Overlying Strata Migration Law in Close Seams Group Under Repeated Mining

The Roof Breaking Characteristics and Overlying Strata Migration Law in Close Seams Group Under Repeated Mining

Study on Evolution Characteristics of Regenerated Roof Structure in Downward Mining of Bifurcated Coal Seam

Investigation of the Optimal Layout of the Roadway in Closely Spaced Ultra‐Thick Coal Seams Mining with Remaining Coal Pillars

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