scholarly journals Study on Overlying Strata Movement and Surface Subsidence of Coal Workfaces with Karst Aquifer Water

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 169
Author(s):  
Yuliang Wang ◽  
Guiyi Wu ◽  
Yang Liu ◽  
Zhanbo Cheng
Keyword(s):  
Numerical Model ◽  
Water Inrush ◽  
Karst Aquifer ◽  
Theory Model ◽  
Surface Subsidence ◽  
Strata Movement ◽  
Maximum Value ◽  
Wide Range ◽  
Overlying Strata Movement ◽  
Overlying Strata

The overlying strata layers of coal workfaces with karst aquifer water normally causes serious safety problems due to the precipitation, drainage and water inrush, such as a wide range and long term of surface subsidence. In this study, by taking 10,301 working faces of the Daojiao coal mine in Guizhou Province as the engineering background, the numerical model of water-bearing strata with fluid-solid coupling was established by using UDEC to illustrate the laws of overlying strata movement and surface subsidence. A theory model was proposed to calculate the surface settlement caused by the drainage of aquifer based on the principle of effective stress modified by the Biot coefficient αb. The results showed that the corresponding maximum value (0.72 m) and the range of the surface subsidence with the occurrence of karst aquifer water were larger than that of the overlying strata without karst aquifer water (e.g., the maximum value of surface subsidence with 0.1 m). Moreover, the surface subsidence caused by the drainage of aquifer accounted for 17.8% of the total surface subsidence caused by coal mining. According to the field monitoring of surface subsidence in 10,301 working faces, the maximum value was 0.74 m, which was highly consistent with the results of numerical simulation and theoretical analysis. It verified the accuracy and reliability of the numerical model and the theory model in this study.

scholarly journals The Influences of Key Strata Compound Breakage on the Overlying Strata Movement and Strata Pressure Behavior in Fully Mechanized Caving Mining of Shallow and Extremely Thick Seams: A Case Study

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Junmeng Li ◽  
Yanli Huang ◽  
Jixiong Zhang ◽  
Meng Li ◽  
Ming Qiao ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Abutment Pressure ◽  
Simulation Software ◽  
Strata Movement ◽  
Key Strata ◽  
Pressure Behavior ◽  
Ground Pressure ◽  
Working Face ◽  
Overlying Strata Movement ◽  
Overlying Strata

In order to analyze the impact of compound breakage of key strata on overlying strata movement and strata pressure behavior during the fully mechanized caving mining in shallow and extremely thick seams, this paper took the 1322 fully mechanized caving face in Jindi Coal Mine in Xing County as the engineering background. Under the special mining and geological condition mentioned above, UDEC numerical simulation software was applied to research the engineering problems, and results of numerical simulation were verified through the in-site measurement. The research results showed that during the fully mechanized caving mining in shallow and extremely thick seams, the inferior key strata affected by mining movement behaved in the mode of sliding instability and could not form the stable structure of the voussoir beam after breaking and caving. In addition, the main key strata behaved in the mode of rotary instability, and the caving rocks behind the goaf were gradually compacted because of the periodic instability of the main key strata. With the continuous advance of the working face, the abutment pressure of the working face was affected by the compound breakage and periodic instability of both the inferior key strata and the main key strata, and the peaks of the abutment pressure presented small-big-small-big periodical change characteristics. Meanwhile, the risk of rib spalling ahead of the working face presented different levels of acute or slowing trends. The actual measurement results of ground pressure in the working face showed that, in the working process, the first weighting interval of the inferior key strata was about 51 m and its average periodic weighting interval was about 12.6 m, both of which were basically consistent with the results of numerical simulation. The research has great significance in providing theoretical guidance and practical experience for predicting and controlling the ground pressure under the similar mining and geological conditions.

Overlying strata movement law of continuous mining and continuous backfilling cemented-fill mining

2021 ◽  
Vol 80 (20) ◽  
Author(s):  
Hai Lin ◽  
Renshu Yang ◽  
Bin Lu ◽  
Yongliang Li ◽  
Shizheng Fang ◽  
...  
Keyword(s):  
Strata Movement ◽  
Continuous Mining ◽  
Overlying Strata Movement ◽  
Overlying Strata

The Application of Similar Material in the Simulation of Overlying Strata Movement in High Inclined Seam in Dongbaowei Mine

2012 ◽  
Vol 600 ◽  
pp. 194-198 ◽  
Author(s):  
Ming Ming Wen
Keyword(s):  
Coal Seam ◽  
Reference Value ◽  
Geological Condition ◽  
Similar Material ◽  
Strata Movement ◽  
Support Measures ◽  
Working Face ◽  
Overlying Strata Movement ◽  
Similar Material Simulation ◽  
Overlying Strata

Studying on the characteristics of the overlying strata movement in high inclined coal seam, the similar material is applied in the simulation model which was built based on the similar material simulation theory and high inclined seam geological condition of Dongbaowei coal mine. The picture and displacement of overlying strata were obtained from the similar material simulation. As a result, the characteristics of the fracture and movement of overlying strata above the full mechanized working face in high inclined seam. This paper proposes some support measures to improve the safety of the working face. These provide significance theoretical guidance and reference value for other working face in high inclined seam.

scholarly journals Overlying strata movement with ground penetrating radar detection in close-multiple coal seams mining

2019 ◽  
Vol 15 (8) ◽  
pp. 155014771986985 ◽  
Author(s):  
Yang Li ◽  
Jiachen Wang ◽  
Yiding Chen ◽  
Zhipeng Wang ◽  
Jianpeng Wang
Keyword(s):  
Coal Seam ◽  
Ground Penetrating Radar ◽  
Longwall Mining ◽  
The United States ◽  
Coal Seams ◽  
Strata Movement ◽  
Longwall Panel ◽  
Ground Penetrating ◽  
Overlying Strata Movement ◽  
Overlying Strata

Longwall mining is a productive mining method that has been widely used in China, the United States, Australia, and Europe. However, due to the subsidence caused by coal mining activities, the phenomenon is complex, longwall mining brings the overburden movement issues accompany with the coal recovery. In subsidence trough, the resulting strata and surface ground movements are regarded as largely contemporaneous with mining, producing more or less direct effects of natural ecology. Ground penetrating radar has been widely used in geological hazard detection due to its high precision, but it is rarely employed in underground measuring the overlying strata movement above the longwall panel. In this article, there are five close-multiple coal seams (5#, 7#, 8#, 9#, 12# seams) within 70 m distance to be monitored in Qian Jiaying coal mine of Kailuan Coal Company in Hebei province. The 7#, 8#, 9#, 12# coal seams were already excavated in sequence. So the 5# coal seam is overmining above the gobs of four coal seams at the top. The ZTR12-series ground penetrating radar equipment is used to detect the development of fractures under the floor of the 5# coal seam. The ZTR12-series ground penetrating radar system has the capability of large depth detection and explosion proof to adapt to the working environment of underground coal mines and can realize fine detection and accurate identification. The maximum detection distance of reflection method can reach 50 m. The measurement results show that the 5# coal seam is in the fracture zone above the gobs of four coal seams, and the caved zone of lower coal seam develops to fine sandstone of the 5# coal seam floor. The ground penetrating radar has shown much promise in the detection of overlying strata movement.

scholarly journals Overlying Strata Movement Laws Induced by Longwall Mining of Deep Buried Coal Seam with Superhigh-Water Material Backfilling Technology

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Fangtian Wang ◽  
Qi Ma ◽  
Gang Li ◽  
Chengguo Wu ◽  
Guangli Guo
Keyword(s):  
Coal Seam ◽  
Field Experiments ◽  
Longwall Mining ◽  
Ecological Environment ◽  
Water Volume ◽  
Mine Pressure ◽  
Strata Movement ◽  
Coal Resources ◽  
Overlying Strata Movement ◽  
Overlying Strata

The “Three Under Mining” (mining under the buildings, the railways, and the waters) coal resources are stored in the central and eastern China. Many large-scale mine disasters occurred due to overburden strata movement and surface subsidence. Longwall mining with superhigh-water material backfilling technology has been improved efficiently to prevent the underground disasters and protect the surface ecological environment. Since underground mine pressure behavior and overlying strata movement are influenced by the backfilling strength and backfilling rates, rational design of backfilling parameters is key to realize the green mining of deep buried coal seams. Based on the combination of geological and production conditions of a deep buried coal seam with composite beam theory, the roof fracture distance was analyzed. The software of UDEC was used to simulate the overlying strata movement laws affected by the different backfilling strength and backfilling rates. With the comparative analysis of the vertical displacement movements and the vertical stress distributions, the reasonable filling rate and water volume fraction were determined to be 90% and 95%, respectively. According to the field experiments, the underground dynamic load was low enough for the safe mining, and the village building can be kept in a stable state with the application of the backfilling technology. The research results in a scientific basis for the coordinated development between the safe and efficient mining of deep buried coal resources and protection of the surface ecological environment.

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