Stability Evaluation Method for Gateways in Closely Spaced Coal Seams and Surrounding Rock Control Technology

2018 ◽  
Vol 43 (10) ◽  
pp. 5469-5485 ◽  
Author(s):  
Minglei Zhang ◽  
Yidong Zhang
Keyword(s):  
Evaluation Method ◽  
Surrounding Rock ◽  
Control Technology ◽  
Stability Evaluation ◽  
Coal Seams ◽  
Surrounding Rock Control

scholarly journals Research on the Reasonable Coal Pillar Width and Surrounding Rock Supporting Optimization of Gob-Side Entry under Inclined Seam Condition

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Li-li Jiang ◽  
Zeng-qiang Yang ◽  
Gang-wei Li
Keyword(s):  
Stress Field ◽  
Control Mechanism ◽  
Coupling Effect ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Control Technology ◽  
Pillar Width ◽  
Monitoring Methods ◽  
Anchor Cable ◽  
Surrounding Rock Control

In order to study the optimal coal pillar width and surrounding rock control mechanism of gob-side entry under inclined seam condition, the 130205 return air entry adjacent to 130203 gob in Yangchangwan No. 1 well is taken as a typical engineering background. By means of engineering background analysis, theoretical analysis based on inside and outside stress field, numerical simulation by FLAC3D software, and in situ industrial test and relevant monitoring methods, the optimal coal pillar width and surrounding rock control technology are obtained. The results show that the influence range of inside stress field is about 12.2∼12.8 m based on theoretical calculation result; under the influence of 10 m coal column, the overall deformation of the roadway is relatively small and within the reasonable range of engineering construction, so the width of the coal pillar along the return air roadway is set to 10 m which is more reasonable; the cross-section characteristics of special-shaped roadway lead to asymmetric stress distribution and fragmentation of surrounding rock, and then the asymmetric surrounding rock control technology under the coupling effect of roof prestressed anchor + high-strength single anchor cable + truss anchor cable support is proposed. The monitoring results of this support method are effective for the maintenance of gob-side entry, and the study conclusions provide new guidance for the surrounding rock control mechanism of gob-side entry under inclined seam conditions.

scholarly journals Gob-Side Entry Retained with Soft Roof, Floor, and Seam in Thin Coal Seams: A Case Study

2020 ◽  
Vol 12 (3) ◽  
pp. 1197 ◽  
Author(s):  
Zhijun Tian ◽  
Zizheng Zhang ◽  
Min Deng ◽  
Shuai Yan ◽  
Jianbiao Bai
Keyword(s):  
Mining Industry ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Mine Pressure ◽  
Coal Seams ◽  
Rock Stability ◽  
Working Face ◽  
Geological Conditions ◽  
Surrounding Rock Control

Gob-side entry retained technology is of great significance to develop coal mining industry sustainably, which can improve the coal recovery rate by mining without the coal pillar. However, scholars and researchers pay little attention to the gob-side entry retained with soft roof, floor, and seam in thin coal seams. In this study, the difficulties and key points of surrounding rock control for gob-side entry retained with soft roof, floor, and seam in thin coal seams were firstly proposed. Secondly, the mechanical model of the interaction between the roadside backfill body and the roof for gob-side entry retained with soft roof, floor, and seam in thin coal seams was established, and the relevant parameters were designed. Finally, the above results were verified by the engineering practice of gob-side entry retained technology and the monitoring of mine pressure on the 1103 working face of the Heilong Coal Mine. Moreover, the effect factors of surrounding rock stability for gob-side entry retained with soft roof, floor, and seam in thin coal seams were discussed using the discrete element method. The results could provide guidance for gob-side entry retained with soft roof, floor, and seam in thin coal seams under similar geological conditions.

scholarly journals On-Site Monitoring for the Stability Evaluation of a Highway Tunnel above Goaves of Multi-Layer Coal Seams

2021 ◽  
Vol 11 (16) ◽  
pp. 7383
Author(s):  
Guangtao Cai ◽  
Wanghua Sui ◽  
Shenglin Wu ◽  
Jilin Wang ◽  
Jiaxing Chen
Keyword(s):  
Coal Seam ◽  
Evaluation Method ◽  
Safety Evaluation ◽  
Shanxi Province ◽  
Stability Evaluation ◽  
Coal Seams ◽  
Highway Tunnel ◽  
Site Monitoring ◽  
The Stability ◽  
The Individual

This paper presents the on-site monitoring of a medium–long highway tunnel constructed above a goaf of a multi-layer coal seam, in order to evaluate and maintain safety during operation. The case study of the Tianzimiao medium–long highway tunnel in Shanxi province was conducted above a goaf of a multi-layer coal seam with typical geological and engineering conditions in China, where a total of four coal seams (seam no. 3, 8, 12, and 15) were mined out with a total thickness of up to 11 m. Methods including data collection, engineering geological survey, drilling, geophysical prospecting, testing, and on-site monitoring were adopted, and a geo-mechanical model was established to conduct the research. Stratified monitoring was applied to investigate the individual settlement and deformation of the four layers of the goaf below, and a prediction of the possible deformation in tunnel floor ground was made based on the stratified measurements. The settlement of the tunnel sidewall, the internal stress in the fractured zone of the surrounding rock, and the deformation above the tunnel entrance were also monitored, and the monitoring data were compared with the numerical simulation results for the safety evaluation of the tunnel. The results show that the current tunnel deformation values and trend are both within the safety scope of the evaluation and prediction. The stability evaluation method for the multi-layer goaf used in this paper and the long-term on-site monitoring and timely feedback during operation is helpful to ensure the safe use of the tunnels above the goaves of multi-layer thick coal seams.

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