scholarly journals Stability Analysis of Roadway Groups under Multi-Mining Disturbances

2021 ◽  
Vol 11 (17) ◽  
pp. 7953
Author(s):  
Yuantian Sun ◽  
Ruiyang Bi ◽  
Qingliang Chang ◽  
Reza Taherdangkoo ◽  
Junfei Zhang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Coal Pillar ◽  
Stability Control ◽  
Surrounding Rock ◽  
Key Strata ◽  
Working Face ◽  
Roadway Stability ◽  
Mining Disturbance ◽  
Mining Face ◽  
The Stability

The roadway stability has been regarded as the main challenging issue for safety and productivity of deep underground coal mines, particularly where roadways are affected by coal mining activities. This study investigates the −740 m main roadway in the Jining No. 2 Coal Mine to provide a theoretical basis for the stability control of the main deep roadway affected by disturbances of adjacent working activities. Field surveys, theoretical analyses, and numerical simulations are used to reveal mechanisms of the coal mining disturbance. The field survey shows that the deformation of roadway increases when the work face advances near the roadway group. Long working face mining causes the key strata to collapse based on the key strata theory and then disturbs the adjacent roadway group. When the working face is 100 m away from the stop-mining line, the roadway group is affected by the mining face, and the width roadway protection coal pillar is determined to be about 100 m. Flac3D simulations prove the accuracy of the theoretical result. Through reinforcement and support measures for the main roadway, the overall strength of the surrounding rock is enhanced, the stability of the surrounding rock of the roadway is guaranteed, and the safe production of the mine is maintained.

scholarly journals Stability Control of a Goaf-Side Roadway under the Mining Disturbance of an Adjacent Coal Working Face in an Underground Mine

2019 ◽  
Vol 11 (22) ◽  
pp. 6398
Author(s):  
Houqiang Yang ◽  
Changliang Han ◽  
Nong Zhang ◽  
Changlun Sun ◽  
Dongjiang Pan ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Stability Control ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Key Strata ◽  
Coal Recovery ◽  
Working Face ◽  
Underground Coal Mines ◽  
Mining Disturbance ◽  
The Stability

Goaf-side roadway driving could not only notably reduce the loss of coal resources and improve the coal recovery rates, but also greatly mitigate the imbalance between excavation speed and production needs, which are able to prolong the service life of the mine and are pivotal to sustainable and efficient development of underground coal mines. However, it is difficult to control the stability of the goaf-side roadway, especially under mining disturbance of another adjacent coal working face. In order to control the stability of the goaf-side roadway, Haulageway 1513 in the Xinyi Coal Mine of China, under mining disturbance, theoretical analysis, numerical simulation, and engineering practice were carried out to reveal the mechanism of overburden key strata fracture, stress distribution, and deformation characteristics of the surrounding rock of the goaf-side roadway due to mining disturbance. Results showed that some key strata above Goaf 1512 did not fracture due to the influence of the strata caving angles. However, these key strata would fracture and break into rock blocks when suffering from mining disturbance of the adjacent coal working face, which changed the stress distribution and increased the deformations of the surrounding rock of the goaf-side roadway. The combined techniques of pressure relief and bolt support were proposed and carried out to control the stability of the goaf-side roadway. Engineering practice indicated that the maximum deformations of the roof and sidewall-to-sidewall were 220 mm and 470 mm, respectively. The deformations of the goaf-side roadway under mining disturbance were efficiently controlled.

scholarly journals The Stability of Roadway Groups under Rheology Coupling Mining Disturbance

2021 ◽  
Vol 13 (21) ◽  
pp. 12300
Author(s):  
Sen Yang ◽  
Guichen Li ◽  
Ruiyang Bi ◽  
Bicheng Yao ◽  
Ruiguang Feng ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Coal Pillar ◽  
Mine Safety ◽  
Key Strata ◽  
Deep Well ◽  
Working Face ◽  
Safety Production ◽  
Mining Disturbance ◽  
The Stability ◽  
And Control

The deep roadway groups play an important role in transportation and ventilation in coal mine production. Therefore, it is very important to comprehensively analyze the coupling effect of rheological deformation and coal mining on the stability of the roadway groups. In this paper, the disturbance effects of different stop-mining lines on roadway groups under long-term rheology were investigated by numerical simulation, and the failure mechanism of roadway groups with large sections and multiple disturbances in a deep well was revealed. The results show that the long working face will lead to the collapse of key strata, and the influence range will spread to the adjacent roadway groups. When the distance between the working face and the stop-mining line is 100 m, the roadway groups cannot be affected by the working face mining, and the reserved width of the coal pillar can be determined to be 100 m, which increases the stability of the roadway’s surrounding rock and maintains the mine safety production. This paper aims to provide a reference for groups design and control under similar conditions.

scholarly journals Study of the Stability Control of the Rock Surrounding Double-Key Strata Recovery Roadways in Shallow Seams

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Cheng Zhu ◽  
Yong Yuan ◽  
Zhongshun Chen ◽  
Zhiheng Liu ◽  
Chaofeng Yuan
Keyword(s):  
Engineering Application ◽  
Stability Control ◽  
Surrounding Rock ◽  
Control Effect ◽  
Pressure Relief ◽  
Support Design ◽  
Key Strata ◽  
Fracture Development ◽  
Surrounding Rock Control ◽  
The Stability

The stability control of the rock surrounding recovery roadways guarantees the safety of the extraction of equipment. Roof falling and support crushing are prone to occur in double-key strata (DKS) faces in shallow seams during the extraction of equipment. Therefore, this paper focuses on the stability control of the rock surrounding DKS recovery roadways by combining field observations, theoretical analysis, and numerical simulations. First, pressure relief technology, which can effectively release the accumulated rock pressure in the roof, is introduced according to the periodic weighting characteristics of DKS roofs. A reasonable application scope and the applicable conditions for pressure relief technology are given. Considering the influence of the eroded area on the roof structure, two roof mechanics models of DKS are established. The calculation results show that the yield load of the support in the eroded area is low. A scheme for strengthening the support with individual hydraulic props is proposed, and then, the support design of the recovery roadway is improved based on the time effects of fracture development. The width of the recovery roadway and supporting parameters is redesigned according to engineering experience. Finally, constitutive models of the support and compacted rock mass in the gob are developed with FLAC3D software to simulate the failure characteristics of the surrounding rock during pressure relief and equipment extraction. The surrounding rock control effects of two support designs and three extraction schemes are comprehensively evaluated. The results show that the surrounding rock control effect of Scheme 1, which combines improved support design and the bidirectional extraction of equipment, is the best. Engineering application results show that Scheme 1 realizes the safe extraction of equipment. The research results can provide a reference and experience for use in the stability control of rock surrounding recovery roadways in shallow seams.

scholarly journals Movement Laws of Overlying Strata above a Fully Mechanized Coal Mining Face Backfilled with Gangue: A Case Study in Jiulishan Coal Mine in Henan Province, China

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Zhengkai Yang ◽  
Zhiheng Cheng ◽  
Zhenhua Li ◽  
Chunyuan Li ◽  
Lei Wang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Main Roof ◽  
Surrounding Rock ◽  
Surface Subsidence ◽  
Key Strata ◽  
Key Stratum ◽  
Mining Face ◽  
Failure Depth ◽  
Gangue Backfilling ◽  
Overlying Strata

The aim of this study is to obtain movement laws of overlying strata above a fully mechanized coal mining face backfilled with gangue and solve the problem of surface subsidence during coal mining. This study was carried out based on gangue backfilling mining of Jiulishan Coal Mine (Jiaozuo City, Henan Province, China) from the perspectives of deformation of backfilled gangue under compaction, surrounding rock of a stope, and activities of key strata. The method combining with rock mechanics, viscoelastic mechanics, control theory of rock mass under mining, and numerical simulation was used based on physical and mechanical characteristics of backfilled gangue. On this basis, the research analyzed the temporal-spatial relationships of activities of surrounding rock of the stope, compressive deformation of backfilling body, failure depth of the floor, deformation characteristics of the main roof with laws of surface subsidence. The movement characteristics of overlying strata above the fully mechanized coal mining face backfilled with gangue and the traditional fully mechanized mining face were compared. It is found that, under the same conditions of overlying strata, movement laws of overlying strata are mainly determined by the mining height of coal seams and the heights of a caving zone and a fracture zone are nearly linearly correlated with the mining height. Through analysis based on thin-plate theory and key stratum theory, the location of the main roof of the fully mechanized coal mining face backfilled with gangue in coal seams first bending and sinking due to load of overlying strata was ascertained. Then, it was determined that there are two key strata and the main roof belongs to the inferior key stratum. By using the established mechanical model for the main roof of the fully mechanized coal mining face backfilled with gangue and the calculation formula for the maximum deflection of the main roof, this research presented the conditions for breaking of the main roof. In addition, based on the theoretical analysis, it is concluded that the main roof of the fully mechanized coal mining face backfilled with gangue does not break, but bends. The numerical simulation results demonstrate that, with the continuous increase of strength of backfilled gangue, the stress concentration degree of surrounding rock reduces constantly, so does its decrease amplitude. Moreover, the compressive deformation of backfilling, failure depth of the floor, and bending and subsidence of the main roof continuously decrease and tend to be stable. The mechanical properties of backfilling materials determine effects of gangue backfilling in controlling surface subsidence. Gangue backfilling can effectively control movement of overlying strata and surface subsidence tends to be stable with the increase of elastic modulus of gangue.

scholarly journals Deformation Rules for Surrounding Rock in Directional Weakening of End Roofs of Thin Bedrocks and Ultrathick Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Fei Liu ◽  
Zhanguo Ma ◽  
Yongsheng Han ◽  
Zhimin Huang
Keyword(s):  
Abutment Pressure ◽  
Main Roof ◽  
Stability Control ◽  
Surrounding Rock ◽  
Western China ◽  
Resource Exploitation ◽  
Failure Characteristics ◽  
Key Strata ◽  
Working Face ◽  
Geological Conditions

With the deployment of China’s energy strategy in the western regions, complex geological mining conditions such as thin bedrock and ultrathick seams in western China have caused a series of problems such as serious deformation of the surrounding rock at the ends of the working face and the increase in the lead abutment pressure of the roadways; the research on end roof deformation in the resource exploitation in western China has become one of the great demands of the industry. Based on the failure characteristics of rock mass, relying on the actual mining geological conditions of a coal mine in Inner Mongolia, the failure characteristics of the overlying rock strata under the influence of mining were simulated and analyzed using similar material simulation experiment, which intuitively reproduced the failure and deformation processes of the immediate roof, main roof, and key strata and revealed the mechanical mechanism of the directional weakening of the end roof. It is of great significance for the stability control of the surrounding rock at the end of the fully mechanized caving face in the thin bedrocks and ultrathick seams, reducing the abutment pressure of gate roadway and controlling the spontaneous combustion of residual coal in the goaf.

The Stability Control Technology of Crosscut while Mining without Coal Pillar in Steep Seam

2011 ◽  
Vol 90-93 ◽  
pp. 2073-2079
Author(s):  
Yu Feng Wang ◽  
Zhi Qiang Liu ◽  
Bin Song Jiang
Keyword(s):  
Support System ◽  
Coal Pillar ◽  
Stability Control ◽  
Surrounding Rock ◽  
Steep Seam ◽  
Floor Rock ◽  
Long Term Stability ◽  
Rock Collapse ◽  
The Stability

In order to improve the mining benefit of coal resources, Chang Gouyu Coal Mine carried out the technology of mining without coal pillar in steep seam. The key of the technology was to ensure a long-term stability of the cross-entry roadway across the seam. Through the analysis of the nature of steep seam roof and floor rock, and based on the stability analysis and loose circle measured of surrounding rock of crosscut roadway, we brought forward adopting shotcrete rockbolt mesh and U-shaped steel complex support structure system. This complex support system could flex lengthways and compress in radial direction. The entirety integrated with the surrounding rock, and they formed into a whole. Application of the complex support system could effectively control the deformation of the surrounding rock collapse, and maintain the stability of the crosscut.

Stress Shell Mechanical Mechanism of Fully-Mechanized Face Enhancing the Upper Limit for Coal Mining and Risk Analysis of Support Break-Off

2012 ◽  
Vol 524-527 ◽  
pp. 466-470
Author(s):  
Jun Ling Hou ◽  
Yan Sun
Keyword(s):  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mining ◽  
Surrounding Rock ◽  
Mechanical Environment ◽  
Upper Limit ◽  
Working Face ◽  
Distribution Rule ◽  
Geological Conditions ◽  
Mining Face

Based on the geological conditions and specific mining technology conditions of the 11014 mining face of Panbei mine in HuaiNan mining group ,using the FLAC3D software, simulate the stress distribution rule and disruption field distribution rule of surrounding rock of Fully-Mechanized face enhancing the upper limit for coal mining along the tendency and trend of coal seam by different mining speed of 6 m/d, 4 m/d and 2 m/d. draw the conclusion that enhancing the mining speed can alleviate the pressure of the working face ,improve the working face mechanical environment,and reduce the extent of the failure field.It provides the theory basis and reference for Fully-Mechanized face enhancing the upper limit for coal mining under similar conditions.

scholarly journals Simulation Analysis and Engineering Application of Retaining Width of Waterproof Coal Pillar in Island Working Face

2021 ◽  
Author(s):  
Lili Zheng ◽  
Zheng Gao
Keyword(s):  
Service Life ◽  
Simulation Analysis ◽  
Engineering Application ◽  
Coal Pillar ◽  
Surrounding Rock ◽  
Simulation Research ◽  
Working Face ◽  
Before And After ◽  
Mining Face ◽  
Coal Pillars

The old mining area in Pingdingshan coalfield has the following problems: long mining service life, many remaining coal pillars, and great difficulty in mining; to extend the service life of the mine, realize cost saving and efficiency increasing, it is urgent to recover the remaining coal pillars, but the mining of isolated island face faces the problem of reasonable retention of waterproof coal pillars, if the protection is not good, it is easy to cause mine water damage and increase the mining cost. Therefore, in view of the practical engineering problems faced by the field, aiming at eliminating or reducing the goaf water disaster, this paper adopts numerical simulation research methods to optimize the original design scheme and carry out comparative analysis, dynamically reappear the surrounding rock stress field, displacement field and plastic failure law under multi face mining and roadway mining, and carry out engineering practice application. The results show that there is a certain thickness of elastic core area before and after mining with 25m coal pillar width. The deformation of surrounding rock is small, which is conducive to roadway maintenance, without obvious stress concentration. It can meet the actual needs of the project. The mining face has achieved safe mining, without water inrush accident in the goaf, and the coal resources have been recovered to the maximum extent. The research results are left over to similar mining areas in China The safe recovery of coal pillar can be used for reference.

scholarly journals Stability of "Support-Surrounding Rock" System for Fully Mechanized Longwall Mining in Steeply Dipping Coal Seams

2021 ◽  
Author(s):  
Luo Shenghu ◽  
tong wang ◽  
Wu Yongping ◽  
Huangfu Jingyu ◽  
Zhao Huatao
Keyword(s):  
Coal Seam ◽  
Longwall Mining ◽  
Stability Control ◽  
Surrounding Rock ◽  
Coal Seams ◽  
Physical Test ◽  
Rock System ◽  
Working Face ◽  
The Stability ◽  
Mining Height

Abstract The key to the safe and efficient longwall mining of steeply dipping seams lies in the stability control of the "support-surrounding rock" system. This paper analyzes the difficulty of controlling the stability of the support during the longwall mining process of steeply dipping coal seams in terms of the characteristics of the non-uniform filled-in gob using a combination of physical test, theoretical analysis and field measurements. Considering the floor as an elastic foundation, we built a "support-surrounding rock" mechanical model based on data obtained on "support-surrounding rock" systems in different regions and the laws of support motion under different load conditions. Our findings are summarized as follows. First, depending on the angle of the coal seam, the caving gangue will roll (slide) downward along the incline, resulting in the formation of a non-uniform filling zone in the deep gob in which the lower, middle, and upper sections are filled, half-filled, and empty, respectively. In addition, an inverted triangular hollow surface is formed on the floor of the gob in the middle and upper sections behind the support. Furthermore, as the angle of the coal seam, length of the working face, and mining height increase, the characteristics of the non-uniform filled-in gob are enhanced. Second, we found that, as a result of support by the gangue, the "support-surrounding rock" system is relatively stable in the lower part of the working face while, in the middle and upper sections of the working face, the contact method and loading characteristics of the support are more complicated, making stability control difficult. Third, the magnitude and direction of the load, action point, and mining height all affect the stability of the support to varying degrees, with the tangential load and action position of the roof load having the most significant impacts on the stability of the support. Under loading by the roof, rotation and subsidence of the support inevitably occur, with gradually increasing amplitude and effects on the inter-support and sliding forces. Finally, we found that it is advisable in the process of moving the support to adopt "sliding advance of support" measures and to apply a "down-up" removal order to ensure overall stability. These research results provide reference and guidance of significance to field practice production.

Laws of Formation and Evolution of Pressure Arch in Coal Mining Adjoining Rock

2011 ◽  
Vol 243-249 ◽  
pp. 2596-2600
Author(s):  
Xiao Li Du ◽  
Hong Wei Song ◽  
Jie Chen
Keyword(s):  
Numerical Simulation ◽  
Coal Mining ◽  
Vertical Direction ◽  
Stress Transfer ◽  
Surrounding Rock ◽  
Coefficient Variation ◽  
Working Face ◽  
Formation And Evolution ◽  
Mining Face ◽  
Adjoining Rock

Based on numerical simulation of computing Software ANSYS, the curve of arching coefficient variation of pressure arch due to actual mining was analyzed aiming to a special mining face, the law of stress transfer and change in surrounding rock was discussed, and the evolving features and characteristics of pressure arch was obtained. The analysis and discussion show the following facts: Arch body will become thicker and stress in the arch body increases with working face’s driving distance increasing; the morphology of pressure arch transits from ellipsoid with long axis in the vertical direction to ellipsoid with long axis in the horizontal direction along the trend of working face; along the tendency of working face, the morphology of pressure arch is a ellipsoid with long axis in the vertical direction.

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