Characteristics of Discontinuous Surface Deformation Due to Mining in Hard, Thick Bedrock: A Case Study
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Coal mining at Zhaizhen coal mine has resulted not only in continuous deformation of the surface but also discontinuous deformation such as surface cracking and step subsidence. The discontinuous deformation of the surface causes serious damage to the environment, cultivated land and surface buildings in the mining area. This study summarizes and studies the characteristics of discontinuous surface deformation in the western mining area of Zhaizhen coal mine and analyzes the mechanisms by which it occurs. The discontinuous surface deformation is caused by two main types of mechanism. The first results from the characteristics of the overlying strata. Specifically, the bedrock layer is thick (230–260 m) and hard, while the topsoil layer is loose and thin (4–8 m). The loose topsoil layer is not thick or strong enough to absorb the deformation of the hard, thick bedrock, and cracks develop at the surface. The other main cause of discontinuous surface deformation is dislocation at faults and folds under the influence of mining. Moreover, repeated coal mining aggravates the discontinuous surface deformation. In order to effectively control this deformation, fully mechanized mining with gangue filling was adopted in mining area No. 7 of Zhaizhen coal mine and the corresponding surface deformation was monitored. The results show that the gangue-filling method effectively controlled the discontinuous surface deformation and resulted in a maximum surface subsidence with a trend and tendency of 206 mm and 209 mm, respectively and no surface cracks or step subsidence at the surface.
KeywordsThick and hard bedrock Thin and loose layer Discontinuous surface deformation Fault and fold structure Gangue filling
This study was supported by the National Natural Science Foundation of China (51474134, 51774194), Shandong Provincial Natural Science Foundation for Distinguished Young Scholars (JQ201612), Major basic research projects of Shandong Natural Science Foundation (ZR2018ZC0740), Taishan Scholar Talent Team Support Plan for Advantaged and Unique Discipline Areas, Shandong Provincial Key Research and Development Plane (2017GSF17112), Key Research and Development Plane of China (2018YFC0604704) and Graduate student science and technology innovation project of Shandong University of Science and Technology (SDKDYC180201).
- Chen JJ, Tao WD, Huang CF (2013) Study on surface damage of mining under thick alluvium. Chin J Geol Hazard Control 24(1):51–55Google Scholar
- Dai HY (1995) Mechanism and calculation of surface discontinuous deformation. J China Soc 20(6):614–618Google Scholar
- Dai HY, Wang JZ, Hu YJ (1999) Mechanism analysis of discontinuous deformation caused by interlayer weak surface. Mine Surv. 2:29–31+63Google Scholar
- Hu QF, Cui XM, Yuan DB, Deng XB (2012) Formation mechanism of surface cracks caused by thick seam mining and hazard analysis. J Min Saf Eng 29(6):864–869Google Scholar
- Kowalski A, Jędrzejec E, Gruchlik P (2010) Linear discontinuous deformations of the surface in the upper silesian coal basin. Arch Min Sci 55(2):331–346Google Scholar
- Li GQ, Tang J, Wei ZJ, Chen SJ (2013) Research on bridge deformation control technology for the influence of surface cracks in deep mining. China Min Mag 22(8):116–119Google Scholar
- Yang F, Yu HF, Guo JT (2016) Mechanism of mining-induced surface crack by numerical simulation method. J Liaoning Univ Eng Technol 35(6):566–570Google Scholar
- Yin DW, Chen SJ, Chen B, Liu XQ, Ma HF (2018) Strength and failure characteristics of the rock-coal combined body with single joint in coal. Geomech Eng 15(5):1113–1124Google Scholar
- Zhu XJ, Zhao TP, Guo WJ, Chen SJ, Wei ZJ (2013) Study on criterion of surface movement cracks occurred above thick and hard overburden strata. Coal Sci Technol 41(6):26–28+84Google Scholar