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Geomechanics and Engineering Volume 18, Number 4, July20 2019, pages 449-457 DOI: https://doi.org/10.12989/gae.2019.18.4.449 |
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Failure pattern of large-scale goaf collapse and a controlled roof caving method used in gypsum mine |
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Lu Chen, Zilong Zhou, Chuanwei Zang, Ling Zeng and Yuan Zhao
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| Abstract | ||
| Physical model tests were first performed to investigate the failure pattern of multiple pillar-roof support system. It was observed in the physical model tests, pillars were design with the same mechanical parameters in model #1, cracking occurred simultaneously in panel pillars and the roof above barrier pillars. When pillars 2 to 5 lost bearing capacity, collapse of the roof supported by those pillars occurred. Physical model #2 was design with a relatively weaker pillar (pillar 3) among six pillars. It was found that the whole pillar-roof system was divided into two independent systems by a roof crack, and two pillars collapse and roof subsidence events occurred during the loading process, the first failure event was induced by the pillars failure, and the second was caused by the roof crack. Then, for a multiple pillar-roof support system, three types of failure patterns were analysed based on the condition of pillar and roof. It can be concluded that any failure of a bearing component would cause a subsidence event. However, the barrier pillar could bear the transferred load during the stress redistribution process, mitigating the propagation of collapse or cutting the roof to insulate the collapse area. Importantly, some effective methods were suggested to decrease the risk of catastrophic collapse, and the deep-hole-blasting was employed to improve the stability of the pillar and roof support system in a room and pillar mine. | ||
| Key Words | ||
| physical model test; pillar collapse mode; pillars-roof support system; deep hole blasting; Gypsum mining | ||
| Address | ||
| Lu Chen: 1.) School of Civil Engineering, Changsha University of Science and Technology, Changsha, Hunan, 410083, China 2.) School of Resources and Safety Engineering, Central South University, Changsha, Hunan, 410082, China Zilong Zhou and Yuan Zhao: School of Resources and Safety Engineering, Central South University, Changsha, Hunan, 410082, China Chuanwei Zang: 1.) School of Mining and Safety Engineering, Shandong University of Science and Technology, Qingdao 266590, China 2.) Key Laboratory of Mining Disaster Prevention and Control, Qingdao 266590, China Ling Zeng: School of Civil Engineering, Changsha University of Science and Technology, Changsha, Hunan, 410083, China | ||