Rib Spalling And Control In Fully-mechanized Top-coal Caving Face With Large Mining Height

In order to prevent and control serious accidents of rib spalling in fully-mechanized top-coalcaving face with large mining height, rib spalling mechanism is studied in detail and a proper，effective and specific controlling technology is put forward. Then, the orthogonal test andelastic-plastic finite deformation theory are combined to produce reselts that the plastic zones areobviously different in deformation process between top coal and the rib. The cusp catastrophicmodel and rib curve slipping mechanical model are established to derived the mechanicalconditional criterion of hard rib spalling and the safety coefficient formula of weak rib spallingrespectively. Based on the intensity weakening theory of rock parting, rib instability discriminationis researched strictly. Combined with triangular fuzzy algorithm and numerical simulation, keyinfluence factors to rib spalling at workface NO.8107are as follows: support failure rate, workingresistance and tip-to-face distance. According to the support failure rate of solid and hydrauliccomponents coming from the calculation of common cause failure (CCF) model, a combination ribcontrol technology called “Solid-liquid synchronization type”(SLST) failure detection method toreduce support failure rate is proposed, and then the rib control effects are compared amongdifferent regions of work face and before&back failure maintenance. Combined with the databasesystems of rib spalling in fully-mechanized top-coal caving face with large mining height, a set ofrib safety evaluation system is developed in C++language program. The research achieves havebeen applied to8107workface of Tongxin coalmine and other typical coalmine to monitor ribstability, and have brought social and finical benefits promptly.