Movement Boundary Shape of Overburden Strata and Its Influencing Factors

Changchun He, Jialin Xu, Fei Wang and Feng Wang
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Changchun He: School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Jialin Xu: School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Fei Wang: Department of Mining Engineering, Colorado School of Mines, 1600 Illinois street, Golden, CO 80401, USA
Feng Wang: College of Mining and Safety Engineering, State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Provence and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao 266590, China

Energies, 2018, vol. 11, issue 4, 1-22

Abstract: Strata movement boundary is not only a parameter for the prediction of overburden strata movement and deformation but also a key index of setting shafts, roadways and protective coal pillars. Based on physical and mechanical properties of rock mass, the overburden strata are divided into bedrock and unconsolidated stratum. By means of theoretical analysis, physical simulation and numerical simulation, this paper studies the movement boundary shapes of bedrock and unconsolidated stratum, builds fitting equations of movement boundary of the two, analyzes the influence of key strata (KS) on the shape of strata movement boundary, and determines the principle of setting protective coal pillars. The results show that the movement boundaries of bedrock and unconsolidated strata are located at the outside of coal mining boundary. They are concave-upward power function curves that cannot be merged into a smooth one due to their different mechanisms of movement and deformation. The movement boundary of bedrock can approximate a straight line when lithology of the overburden is relatively uniform with thin strata in different positions; the surface movement boundary extends when the overburden has thick and stiff KS that are common in deeply buried coal seam. Therefore, the width of protective coal pillar is small if the movement boundary is regarded as a straight line. According to the curve movement boundary, the protective coal pillar for the passenger roadway of Panel 31010 of Pingdingshan No.1 mine is at least 99.4 m in width, larger than the designed one, which is the actual reason for its deformation and breakage.

Keywords: movement boundary; key strata; unconsolidated stratum; protective coal pillars (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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