Comprehensive research on character of collapse and fracture of thick and large overburden rock in cave mining
LI Shulin1，HU Jingyun2，ZHOU Aimin2，LIN Feng2，YU Zhengfang3
(1. School of Architectural and Civil Engineering，Xiamen University，Xiamen，Fujian 361005，China；2. Changsha Institute of Mining Research Co.，Ltd.，National Metal Mining Engineering and Technology Research Center，Changsha，Hunan 410012，China；
3. Yuxi Dahongshan Mining Co.，Ltd.，Yuxi，Yunnan 653100，China)
Abstract：A bulky mining-out area was formed at Dahongshan iron mine with sublevel caving method. The thickness of overburden is 627 to 750 meter. In order to understand the development of collapse area，fractured zone and high stress concentration zone in overburden so as to prevent the sudden large-scale and dynamic ground pressure disasters，micro-seismic monitoring，tunnel observation and borehole detection methods were used to carry out the comprehensive monitoring and research. Base on the precise location of fracture source with multi-channel micro-seismic monitoring technology，high-stress concentration zone and its developing trend were determined，and then the outer boundary was deduced. At same time，the analysis on fracture types of fracture source with double couples model showed that the tension fracture with volume-increasing accounted for majority of all sources，while the shear failure and mixed failure accounted for minority. The boundary of collapse area，external and internal boundaries of fractured area were determined directly through the artificial observation in special tunnels. The borehole detection as the auxiliary method was used to determine and validate the external boundary of fractured zone. A comprehensive monitoring and analysis were carried out to obtain the caving zone，cracking zone and high stress concentration area in overburden in different periods from 2011 to 2013. The development of high stress zone，cracking zone and caving zone in different periods were also obtained. The studies showed that the caving and cracking processes in overburden were slow and gradual. The sudden and dynamic large-scale collapse disaster would not occur. The conclusion of this paper played an important role in guiding the safe production of the mine.
李庶林1，胡静云2，周爱民2，林 峰2，余正方3. 崩落法上覆厚大岩层崩落及破裂特性综合研究[J]. 岩石力学与工程学报, 2016, 35(9): 1729-1739.
LI Shulin1，HU Jingyun2，ZHOU Aimin2，LIN Feng2，YU Zhengfang3. Comprehensive research on character of collapse and fracture of thick and large overburden rock in cave mining. , 2016, 35(9): 1729-1739.
2016, Vol. 35 
