scholarly journals Bed separation backfill to reduce surface cracking due to mining under thick and hard conglomerate: a case study

2019 ◽  
Vol 6 (8) ◽  
pp. 190880 ◽  
Author(s):  
Dawei Yin ◽  
Shaojie Chen ◽  
Bo Li ◽  
Weijia Guo
Keyword(s):  
Coal Mining ◽  
Surface Deformation ◽  
Control Surface ◽  
Discontinuous Surface ◽  
Surface Cracking ◽  
Subsidence Basin ◽  
Working Face ◽  
Backfill Materials ◽  
Discontinuous Deformation ◽  
Bed Separation

After coal mining, the surface above a goaf may experience the discontinuous deformation under some special geological and mining conditions, such as surface cracking, surface step subsidence and collapse pits. Discontinuous deformation seriously threatens the safety of surface buildings and infrastructures. In this paper, the mechanism of discontinuous surface deformation and surface cracking due to coal mining under thick and hard conglomerate in the Huafeng coal mine was studied using a simulation test on similar materials. Bed separation backfill was then proposed to control surface cracking and to protect the Luli bridge. Because of lithological differences between the conglomerate and relatively weak red strata (beneath the conglomerate), the bed separation occurred between them with the advancement of the working face. When the bed separation span exceeded its breaking span, the conglomerate fractured, causing surface cracking of the downhill area and seriously damaging the stability of the Luli bridge. Three drilling holes were arranged along the strikes of the 1412 and 1613 working faces and nearly 387 000 m 3 of backfill materials (water, fly ash and gangue powder) were injected into the bed separation space to reduce or prevent fracturing of the conglomerate. The compacted backfill body supported the conglomerate and reduced the subsidence of the basin and surface ‘rebound' deformation at the edge of the subsidence basin. Clay in the red strata expanded upon contact with water, and this further backfilled the bed separation zone and supported the conglomerate. The upper and lower structures and foundation of the bridge were reinforced using various methods. It was shown that bed separation backfill effectively controlled conglomerate movement and protected the bridge with a maximum subsidence of 251 mm. No obvious surface cracks were observed near the Luli bridge.

scholarly journals Research on Surface Deformation of Ordos Coal Mining Area by Integrating Multitemporal D-InSAR and Offset Tracking Technology

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Jiaming Yao ◽  
Xin Yao ◽  
Zuoqi Wu ◽  
Xinghong Liu
Keyword(s):  
High Resolution ◽  
Large Deformation ◽  
Coal Mining ◽  
Surface Deformation ◽  
Mining Area ◽  
Deformation Field ◽  
Coal Mining Area ◽  
Working Face ◽  
Offset Tracking ◽  
Tracking Technology

Underground mining in coal mining areas will induce large-scale, large-gradient surface deformation, threatening the safety of people’s lives and property in nearby areas. Due to mining-related subsidence is characterized by fast displacement and high nonlinearity, monitoring this process by using traditional and single interferometric synthetic aperture radar (InSAR) technology is very challenging, and it cannot accurately and quantitatively calculate the deformation of the mining area. In this paper, we proposed a new method that combines both multitemporal consecutive D-InSAR and offset tracking technology to construct a complete deformation field of the coal mining area. Taking into account the accuracy of multitemporal consecutive D-InSAR in calculating small deformation areas and the ability of offset tracking to measure large deformation areas, we utilized their respective advantages to extract the surface influence range and applied an adaptive spatial filtering method to integrate their respective results for inversion of the deformation field. 12 ascending high-resolution TerraSAR-X images (2 m) from September 3, 2018, to October 26, 2019, and 39 descending Sentinel-1 TOPS SAR images from August 5, 2018, to November 4, 2019, in the Ordos Coalfield located at Inner Mongolia, China, were utilized to obtain the whole subsidence field of the working faces F6211 and F6207 during the 454-day mining period. The GPS monitoring station located in the direction of the mining surface is used to verify the accuracy of the above method; at the same time, to a certain extent, the difference between the unmanned aerial vehicle’s DSM data acquired after coal mining and the Shuttle Radar Topography Mission (STRM) DEM can qualitatively verify the accuracy of the results. Our results show that the results of TerraSAR are basically consistent with the deformation trend of GPS data, and that of Sentinel-1 have large errors compared with GPS. The maximum central subsidence reaches ~12 m in the working face F6211 and ~4 m in the working face F6207. In the working face F6207, the good agreement between GPS and TerraSAR results indicated that the method above using high-resolution SAR data could be reliable for monitoring the large deformation area in the mining field.

The Adaptation Analysis of the Fully Mechanized Coal Mining Face of Huopu Mine’s Third Soft Coal Seam

2014 ◽  
Vol 1049-1050 ◽  
pp. 335-338 ◽  
Author(s):  
Fa Quan Liu ◽  
Xue Wen Geng ◽  
Yong Che ◽  
Xiang Cui
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Geological Condition ◽  
Soft Coal ◽  
Working Face ◽  
Mining Face ◽  
Soft Coal Seam ◽  
Working Resistance

To get the maximum coal in front of the working face of the 17# coal seam, we installed a longer beam which is 1.2m in length in the leading end of the original working face supports ZF3000/17/28, and know that working face supports’ setting load and working resistance are lower .We changed the original supports with shield supports ZY3800/15/33 that are adaptable in the geological condition and got the favorable affection.

3D Visual Technology of Geo-Deformation Disasters Induced by Mining Subsidence Based on ArcGIS Engine

2012 ◽  
Vol 500 ◽  
pp. 428-436 ◽  
Author(s):  
Ke Ming Yang ◽  
Jun Ting Ma ◽  
Bo Pang ◽  
Yi Bin Wang ◽  
Ran Wang ◽  
...  
Keyword(s):  
Coal Mining ◽  
Surface Deformation ◽  
Ground Deformation ◽  
Ground Surface ◽  
Horizontal Displacement ◽  
Mining Subsidence ◽  
Underground Coal Mining ◽  
Vertical Movements ◽  
Probability Integral Method ◽  
Arcgis Engine

Mining subsidence often produces significant horizontal and vertical movements at the ground surface, the surface deformation induced by underground coal mining can be predicted by probability integral method, and the surface geo-deformation disasters can be visualized based on GIS components. A three dimensional (3D) visualizing system of surface geo-deformation information is designed and developed with ArcGIS Engine and C# in the study. According to the surface deformation-predicted data induced by underground coal mining in Guobei Coalmine of Huaibei mine field, the extents and degrees of ground deformation disasters are visualized in 3D views for surface vertical subsidence, slope, curvature, horizontal displacement and horizontal strain based on the GIS-developed application platform.

scholarly journals A Mechanical Model of the Overlying Rock Masses in Undersea Coal Mining and a Stress-Seepage Coupling Numerical Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Jie Fang ◽  
Lei Tian ◽  
Yanyan Cai ◽  
Zhiguo Cao ◽  
Jinhao Wen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Coal Mining ◽  
Water Inrush ◽  
Mining Area ◽  
Analysis Model ◽  
Fractured Zones ◽  
Working Face ◽  
Seam Mining ◽  
Overlying Strata

The water inrush of a working face is the main hidden danger to the safe mining of underwater coal seams. It is known that the development of water-flowing fractured zones in overlying strata is the basic path which causes water inrushes in working faces. In the engineering background of the underwater mining in the Longkou Mining Area, the analysis model and judgment method of crack propagation were created on the basis of the Mohr–Coulomb criterion. Fish language was used to couple the extension model into the FLAC3d software, in order to simulate the mining process of the underwater coal seam, as well as to analyze the initiation evolutionary characteristics and seepage laws of the fractured zones in the overlying strata during the advancing processes of the working face. The results showed that, during the coal seam mining process, the mining fractured zones which had been caused by the compression-shear and tension-shear were mainly concentrated in the overlying strata of the working face. Also, the open-off cut and mining working face were the key sections of the water inrush in the rock mass. The condition of the water disaster was the formation of a water inrush channel. The possible water inrush channels in underwater coal mining are mainly composed of water-flowing fractured zones which are formed during the excavation processes. The numerical simulation results were validated through the practical engineering of field observations on the height of water-flowing fractured zone, which displayed a favorable adaptability.

Chapter 11 Coal mining subsidence in the UK

2020 ◽  
Vol 29 (1) ◽  
pp. 291-309 ◽  
Author(s):  
Laurance Donnelly
Keyword(s):  
Coal Mining ◽  
Longwall Mining ◽  
Ground Surface ◽  
Mining Subsidence ◽  
Ground Movement ◽  
Working Face ◽  
Mine Roadway ◽  
Coal Mining Subsidence ◽  
The Uk

AbstractOne of the geohazards associated with coal mining is subsidence. Coal was originally extracted where it outcropped, then mining became progressively deeper via shallow workings including bell pits, which later developed into room-and-pillar workings. By the middle of the 1900s, coal was mined in larger open pits and underground by longwall mining methods. The mining of coal can often result in the subsidence of the ground surface. Generally, there are two main types of subsidence associated with coal mining. The first is the generation of crown holes caused by the collapse of mine entries and mine roadway intersections and the consolidation of shallow voids. The second is where longwall mining encourages the roof to fail to relieve the strains on the working face and this generates a subsidence trough. The ground movement migrates upwards and outwards from the seam being mined and ultimately causes the subsidence and deformation of the ground surface. Methods are available to predict mining subsidence so that existing or proposed structures and land developments may be safeguarded. Ground investigative methods and geotechnical engineering options are also available for sites that have been or may be adversely affected by coal mining subsidence.

scholarly journals Effect of Underground Coal Mining on Slope Morphology and Soil Erosion

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Liu Ning ◽  
Zhao Xiao-Guang ◽  
Song Shi-Jie ◽  
Zhou Wen-Fu
Keyword(s):  
Soil Erosion ◽  
Surface Morphology ◽  
Coal Mining ◽  
Underground Mining ◽  
Slope Gradient ◽  
Underground Coal Mining ◽  
Slope Length ◽  
Natural Slope ◽  
Included Angle ◽  
Working Face

Underground coal mining will cause large-scale surrounding rock movement, resulting in surface subsidence and irreversible deformation of surface morphology, which would lead to geological disasters and ecological environment problems. In this paper, FLAC3D numerical model is built based on the natural slope gradient, slope type, and included angle between the slope and working face, and their influences on the change of surface morphology and soil erosion caused by underground coal mining is studied. Research results show that the change of slope gradient caused by underground mining decreases with the increase of natural slope gradient, while slope length has opposite laws; different slope types have different changes of slope morphology. The order of slope types corresponding to gradient changes is mixed slope < uniform slope < concave slope < convex slope; the length of the concave and uniform slope decreases, and the convex and mixed slope length increases. When the included angle between the slope and working face is 0° ≤ α < 90°, the underground mining will cause the natural slope gradient increase, the change of the slope gradient will increase with the rise of the angle, the slope length will decrease, and the rate of decrease will be reduced with the increase of the angle. Coal mining will cause the increasing of the runoff and erosion modulus of slope, mainly runoff modulus.

scholarly journals Identification of Pavement Model Parameters in the Area of Discontinuous Surface Deformation Based on FWD Tests

2020 ◽  
Author(s):  
Marcin Grygierek ◽  
Krzysztof J. Sternik
Keyword(s):  
Surface Deformation ◽  
Elastic Half Space ◽  
Model Parameters ◽  
In Situ Tests ◽  
Discontinuous Surface ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Reinforcement Design ◽  
Falling Weight

Abstract Determination of the parameters of the pavement model in the linear discontinuous surface deformation (LDSD) area is presented in the article. The values are based on back calculations which involve results obtained from the elastic half-space model and the elastic—perfectly plastic model implemented in the finite element code compared with the results of the pavement deflection measured with Falling Weight Deflectometer (FWD). Based on the results of the calculations which have been matched to the results of the in situ measurements, the obtained values of the parameters of the pavement model within LDSD zone and outside it, were analysed. The results of pavement tests indicate at least a threefold increase in pavement deflections in the discontinuous deformation zone compared to deflections in the sections not affected by LDSD. The results of in situ tests and computational analysis presented in the paper allow their use in pavement reinforcement design in the area of anticipated LDSD.

The Coal Mining Mode of Paste-Like Fill and its Application Prospects

2011 ◽  
Vol 255-260 ◽  
pp. 3744-3748
Author(s):  
Yu Cheng Huang ◽  
Rui Min Feng ◽  
Hong Pan Wang ◽  
Wen Ping Zhao ◽  
Yong Fei Liu
Keyword(s):  
Coal Mining ◽  
Filling Material ◽  
Practical Situation ◽  
Filling Materials ◽  
Working Face ◽  
Main Components ◽  
Application Prospects

The coal mining mode of paste-like fill shows the connotation and characteristics of green mining both in the filling materials and mining backfill technology. Combined with the practical situation of colliery, some main components of the coal mining mode of paste-like fill are introduced emphatically, such as the cemented filling material, the preparation and transportation of filling materials, and filling technology at working face; the application prospects on mining with paste-like fill are analyzed.

scholarly journals Additional Stress on a Buried Pipeline under the Influence of Coal Mining Subsidence

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Ping Xu ◽  
Minxia Zhang ◽  
Zhibin Lin ◽  
Zhengzheng Cao ◽  
Xu Chang
Keyword(s):  
Coal Mining ◽  
Surface Deformation ◽  
Analytical Calculation ◽  
Mining Subsidence ◽  
Ground Subsidence ◽  
Additional Stress ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Probability Integral Method ◽  
Coal Mining Subsidence

Buried pipelines influenced by coal mining subsidence will deform and generate additional stress during surface deformation. On the basis of the coordinating deformation relationship between buried pipeline and its surrounding soils, a stress analysis method of a buried pipeline induced by mining was proposed. The buried pipeline additional stresses were analyzed; meanwhile, a corresponding analysis process of the pipeline stresses was also presented during mining subsidence. Furthermore, based on the ground subsidence along the pipeline predicted in advance by the probability integral method, the additional stresses and Von Mises equivalent stresses and their distributions along the buried pipeline induced by the exploitation of a coal mining working face named 14101 were obtained. Meanwhile, a comparative analysis of additional stresses between simulation and analytical calculation was performed for the deep analysis and reliability of the results presented by the proposed methodology in this paper. The proposed method provides references for analysis of the additional stress and safety of buried pipelines under the influence of mining subsidence.

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