Study on the Support Capacity Determination and Movement Law of Overlying Strata in a Thin-Bedrock Large-Cutting-Height
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ORIGINAL PAPER
Study on the Support Capacity Determination and Movement Law of Overlying Strata in a Thin-Bedrock Large-Cutting-Height Longwall Panel Yu Xiong . Dezhong Kong
. Guiyi Wu . Qiang Li
Received: 16 July 2020 / Accepted: 31 October 2020 Ó Springer Nature Switzerland AG 2020
Abstract The ground pressure control problem in the face area has a negative impact on the safety, production and productivity of a longwall face. This problem becomes worse due to the deeper cover depth and the larger vertical seam thickness. The powered supports can be used to improve the ground pressure control in the face area, thus the determination of support capacity plays an important role in the stability control of surrounding rock. In this research, the movement law of overlying strata and characteristics of roof broken in a thin-bedrock large-cutting-height longwall panel are studied through the physical and numerical modeling. A theoretical model is presented to determine the support capacity. The results show that: The lower main roof lost its stability by sliding while the upper main roof maintained the relative stability by forming a structure of ‘masonry beam’ according to the physical modeling; The stability of the support and coal face is most vulnerable during the roof weighting; The loading capacity of the support is determined to be 15,000 kN by a theoretical analysis according to the roof structure of a deep, thin-bedrock large-cutting-height longwall panel. The application Y. Xiong D. Kong (&) G. Wu Q. Li Mining College, Guizhou University, Guiyang 550025, China e-mail: [email protected] D. Kong Guizhou Coal Mine Design and Research Institute, Guiyang 550025, China
of support in the field also validates the reasonability of the theoretical model. The results may provide guidance for the determination of support resistance in similar geological conditions. Keywords Thin bedrock Large-cutting-height longwall face Coal face stability Support resistance Physical model Numerical model
1 Introduction With the improvement of fully mechanized mining equipment and techniques, the single-pass largecutting-height mining method has been greatly developed and widely adopted for mining thick coal seams in China (Wang 2009; Qian et al. 2010; Liu et al. 2019). The application of this mining method may be limited in extremely complicated geological conditions, especially in thin bedrock, thick mining height, deep coal mines. Those coal seams are widely found in middle-east of China (Zhang et al. 2015; Yang et al. 2016a, b; Wang et al. 2019). Since it is difficult to form a stable ‘‘masonry beam’’ structure in the roof under the condition of thin bedrock and thick loose layer, the roof weighting may occur more frequently and intensively (Wang et al. 2015a, b, 2016a, b). The thick loose layer provides load to the roof and coal face, which may causes the roof cutting along the coal
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Geotech Geol Eng
face and crushing the support (Huang 1999, 2002; Cheng et
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