The size distribution of a muck pile depends not on only the blasting standard but also on the mechanical properties,joint system,and crack density of the rock mass. As,the cracks in the rock masses are especially hea...The size distribution of a muck pile depends not on only the blasting standard but also on the mechanical properties,joint system,and crack density of the rock mass. As,the cracks in the rock masses are especially heavily developed at the limestone quar- ries in Japan,they,along with the joints,have a large impact on the effects of blasting, such as the size of the muck pile.Therefore,if the joint system and/or crack density in a rock mass can be determined and quantitatively evaluated,the blasting operation can be conducted more effectively,efficiently and safely.However,guidelines for designing ap- propriate blasting standards based on the rock mass conditions have not yet been scien- tifically developed.Therefore,blasting tests were conducted on different mines and faces, under different geological conditions and blasting standards,in order to determine the im- pacts of each factor on the effects of blasting.Summarized the results of a series of blast- ing tests and described the impacts of geological conditions on the size of the muck pile produced by blast.展开更多
Based on the geological condition of Zhangxiaolou deep mine in Xuzhou mining area, under 986 m in depth, 20.6-31.6 MPa in maximum horizontal principal stress, and friable and fractured surrounding rock, test researche...Based on the geological condition of Zhangxiaolou deep mine in Xuzhou mining area, under 986 m in depth, 20.6-31.6 MPa in maximum horizontal principal stress, and friable and fractured surrounding rock, test researches on partial relieving pressure were completed for the entry with U-steel arched yielding support. The relieving pressure parameters, technology process and results of springing blasting by boreholes and excavating pockets in the two sides of entry were introduced. It is demonstrated that springing will not be shaped under the condition of single borehole arrangement after exploded, the arrangement by a group, it will make borehole bottom form springing in 0.6-0.8 m in diameter, that convergence of two sides and roof to floor have some increments by using springing blasting for reliving pressure. This kind of method for reliving pressure is not suitable to use in the deep mine, and that the convergence of two sides obviously declined by excavating pocket in two sides, it can be still used in the entry with metal support, while maintenance of entry in deep mines is difficult, and can not be supported by bolt or bolt with wire mesh.展开更多
文摘The size distribution of a muck pile depends not on only the blasting standard but also on the mechanical properties,joint system,and crack density of the rock mass. As,the cracks in the rock masses are especially heavily developed at the limestone quar- ries in Japan,they,along with the joints,have a large impact on the effects of blasting, such as the size of the muck pile.Therefore,if the joint system and/or crack density in a rock mass can be determined and quantitatively evaluated,the blasting operation can be conducted more effectively,efficiently and safely.However,guidelines for designing ap- propriate blasting standards based on the rock mass conditions have not yet been scien- tifically developed.Therefore,blasting tests were conducted on different mines and faces, under different geological conditions and blasting standards,in order to determine the im- pacts of each factor on the effects of blasting.Summarized the results of a series of blast- ing tests and described the impacts of geological conditions on the size of the muck pile produced by blast.
基金Supported by the Key Project of the National Natural Science Foundation （50490273）
文摘Based on the geological condition of Zhangxiaolou deep mine in Xuzhou mining area, under 986 m in depth, 20.6-31.6 MPa in maximum horizontal principal stress, and friable and fractured surrounding rock, test researches on partial relieving pressure were completed for the entry with U-steel arched yielding support. The relieving pressure parameters, technology process and results of springing blasting by boreholes and excavating pockets in the two sides of entry were introduced. It is demonstrated that springing will not be shaped under the condition of single borehole arrangement after exploded, the arrangement by a group, it will make borehole bottom form springing in 0.6-0.8 m in diameter, that convergence of two sides and roof to floor have some increments by using springing blasting for reliving pressure. This kind of method for reliving pressure is not suitable to use in the deep mine, and that the convergence of two sides obviously declined by excavating pocket in two sides, it can be still used in the entry with metal support, while maintenance of entry in deep mines is difficult, and can not be supported by bolt or bolt with wire mesh.
