Pressure relief and structure stability mechanism ofhard roof for gob-side entry retaining
来源期刊：中南大学学报(英文版)2015年第11期
论文作者：HAN Chang-liang ZHANG Nong LI Bao-yu SI Guang-yao ZHENG Xi-gui
文章页码：4445 - 4455
Key words：hard roof; pressure relief; cantilever length; double stress peaks; gob-side entry retaining
Abstract: In order to explore the pressure relief and structure stability mechanism of lateral cantilever structure in the stope under the direct coverage of thick hard roof and its impact on the gob-side entry retaining, a lateral cantilever fractured structural mechanical model was established on the basis of clarification for the stress environment of gob-side entry retaining, and the equation of roof given deformation and the balance judgment for fracture block were obtained. The optimal cantilever length was proposed based on the comparison of roof structural characteristics and the stress, deformation law of surrounding rocks under six different cantilever lengths by numerical simulation method. Double stress peaks exist on the sides of gob-side entry retaining and the entry located in the low stress area. The pressure of gob-side entry retaining can be relieved by reducing the cantilever length. However, due to the impact of arch structure of rock beam, unduly short cantilever would result in insufficient pressure relief and unduly long cantilever would bring larger roof stress which results in intense deformation. Therefore, there is optimal cantilever length, which was 7-8 m in this project that enables to achieve the minimum deformation and the most stabilized rock structure of entry retaining. An engineering case of gob-side entry retaining with the direct coverage of 10 m thick hard limestone roof was put forward, and the measured data verified the reasonability of conclusion.
HAN Chang-liang(韩昌良)1, ZHANG Nong(张农)1, 2, LI Bao-yu(李宝玉)1, SI Guang-yao(司光耀)3, ZHENG Xi-gui(郑西贵)1
(1. School of Mines, Key Laboratory of Deep Coal Resource Mining of Ministry of Education,
China University of Mining and Technology, Xuzhou 221116, China;
2. Hunan Key Laboratory of Safe Mining Techniques of Coal Mines,
Hunan University of Science and Technology, Xiangtan 411201, China;
3. Earth Science and Engineering, Imperial College London, London W6 8EP, England)
Abstract:In order to explore the pressure relief and structure stability mechanism of lateral cantilever structure in the stope under the direct coverage of thick hard roof and its impact on the gob-side entry retaining, a lateral cantilever fractured structural mechanical model was established on the basis of clarification for the stress environment of gob-side entry retaining, and the equation of roof given deformation and the balance judgment for fracture block were obtained. The optimal cantilever length was proposed based on the comparison of roof structural characteristics and the stress, deformation law of surrounding rocks under six different cantilever lengths by numerical simulation method. Double stress peaks exist on the sides of gob-side entry retaining and the entry located in the low stress area. The pressure of gob-side entry retaining can be relieved by reducing the cantilever length. However, due to the impact of arch structure of rock beam, unduly short cantilever would result in insufficient pressure relief and unduly long cantilever would bring larger roof stress which results in intense deformation. Therefore, there is optimal cantilever length, which was 7-8 m in this project that enables to achieve the minimum deformation and the most stabilized rock structure of entry retaining. An engineering case of gob-side entry retaining with the direct coverage of 10 m thick hard limestone roof was put forward, and the measured data verified the reasonability of conclusion.
Key words:hard roof; pressure relief; cantilever length; double stress peaks; gob-side entry retaining
