According to the structural characteristics of gently inclined thin layer rock mass in which lots of weak interlayer existed,the concept of gently inclined thin layer weakness structure was proposed.If single-borehole...According to the structural characteristics of gently inclined thin layer rock mass in which lots of weak interlayer existed,the concept of gently inclined thin layer weakness structure was proposed.If single-borehole measuring method of the acoustic along the conventional arrangement mode was used in measuring the broken rock zone in this structure,the change of the relationship curves (Vp-L) between acoustic p-wave velocity (Vp) and borehole depth (L) would present the irregular feature due to the mechanical characteristics of layered rock mass and harmful effects of weak interlayers,and the scope of broken rock zone couldn't be defined quickly.Based on the analysis of the me- chanical characteristics of layered rock mass,the propagation rule of acoustic and distri- butions characteristics of plastic zone and slip zone in layered rock mass,new arrange- ment mode of acoustic measuring boreholes for broken rock zone in gently inclined thin layer weakness structure was proposed.Namely,the measuring boreholes in two sides were parallel to the strata,the measuring boreholes in the roof and floor perpendicular to the strata.Besides the controlling depth of the measuring boreholes in the scope of the large plastic zones or the large slip zones should be increased.Engineering example showed that new acoustic measuring boreholes arrangement mode had the better appli- cability and could determine the scope of the broken rock zone in the gently inclined thin layer weakness structure quickly.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
基金the National Natural Science Foundation of China(50490274)National Key Project of Scientific and Technical Supporting Programs of China(2006BAB02A02)Guangxi University Research Foundation(X061068)
文摘According to the structural characteristics of gently inclined thin layer rock mass in which lots of weak interlayer existed,the concept of gently inclined thin layer weakness structure was proposed.If single-borehole measuring method of the acoustic along the conventional arrangement mode was used in measuring the broken rock zone in this structure,the change of the relationship curves (Vp-L) between acoustic p-wave velocity (Vp) and borehole depth (L) would present the irregular feature due to the mechanical characteristics of layered rock mass and harmful effects of weak interlayers,and the scope of broken rock zone couldn't be defined quickly.Based on the analysis of the me- chanical characteristics of layered rock mass,the propagation rule of acoustic and distri- butions characteristics of plastic zone and slip zone in layered rock mass,new arrange- ment mode of acoustic measuring boreholes for broken rock zone in gently inclined thin layer weakness structure was proposed.Namely,the measuring boreholes in two sides were parallel to the strata,the measuring boreholes in the roof and floor perpendicular to the strata.Besides the controlling depth of the measuring boreholes in the scope of the large plastic zones or the large slip zones should be increased.Engineering example showed that new acoustic measuring boreholes arrangement mode had the better appli- cability and could determine the scope of the broken rock zone in the gently inclined thin layer weakness structure quickly.
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.
