In order to solve the problems of top-coal inadequate destruction and large amounts of gas emission in mining extra thick and hard coal seam,this study investigated the pre-splitting for deep borehole blasting and gas...In order to solve the problems of top-coal inadequate destruction and large amounts of gas emission in mining extra thick and hard coal seam,this study investigated the pre-splitting for deep borehole blasting and gas pre-draining technologies on top coal.The mechanism of the technologies was systematically expounded based on hard top-coal cracks development obtained by numerical simulation and theoretical analysis.The results show that explosive blasting in the hard rock results in a large number of cracks and large displacement in the rock mass due to the effect of explosion stress.Meanwhile,the thick top-coal caves,and desorbing gas flows along the cracks improve gas extraction.Finally,the pre-splitting for deep borehole blasting and gas pre-draining technologies was applied in No.3802 working face of Shui Liandong Coal Mine,which increases monthly output in the face to 67.34 kt and the drained gas concentration to 86.2%.The drained gas average concentration from each borehole reaches 40%,and the effect is remarkable.展开更多
The stress strength factor, length and opening degree of cracks around boreholes as well as movement regularity Of blockage with the smooth blasting by water coupling are calculated out according to the theories of fr...The stress strength factor, length and opening degree of cracks around boreholes as well as movement regularity Of blockage with the smooth blasting by water coupling are calculated out according to the theories of fracture mechanics and explosion dynamics, and the relation between the pressure in holes and the change of hoIe volume is pointed out, thereby the distance between boreholes is worked out in this paper. For limestone, when uncoupling coefficient is 3,diameter of holes is 100 mm, the hole distance of water coupling smooth blasting is 2. 3 m. The result is consistent with practice.展开更多
Blasting operation dissipates much of the blasting energy in crushing the rock at the borehole and the resulting cracks are randomly oriented. There is very little control of the fracture plane. In order to control th...Blasting operation dissipates much of the blasting energy in crushing the rock at the borehole and the resulting cracks are randomly oriented. There is very little control of the fracture plane. In order to control the fracture plane, many methods have been applied. This paper discusses a new blasting method in which a high degree of fracture control can be achieved while minimizing the ground shock.展开更多
The size distribution of fragmented rocks depends on not only the blasting standard but also the mechanical properties, joint system and crack density of rock mass. As, especially, the cracks in the rock mass are heav...The size distribution of fragmented rocks depends on not only the blasting standard but also the mechanical properties, joint system and crack density of rock mass. As, especially, the cracks in the rock mass are heavily developed at the limestone quarries in Japan, the joints and/or cracks in the rock mass have big impacts on the blasting effects such as the size of fragmented rocks. Therefore, if the joint system and/or crack density in the rock mass can be known and evaluated in quantity, the blasting operation can be done more effectively, efficiency and safety. However, the guideline for designing the appropriate blasting standard based on the rock mass condition such as mechanical properties, joint system and/or distribution of cracks, discontinuities, from the scientific point of view, has not been developed yet. Therefore, a series of blasting tests had been conducted in different mines and faces, geological conditions and blasting standards in order to know the impacts of each factor on the blasting effects. This paper summarizes the results of blasting tests and describes the impacts of rock mass conditions and blasting standard on the size of fragmented rocks.展开更多
This paper theoretically analyzed and discussed the fractures’ initiation, propagation and arrest of grooved borehole blasting under the function of explosion, and provided the optimistic values of blasting parameter...This paper theoretically analyzed and discussed the fractures’ initiation, propagation and arrest of grooved borehole blasting under the function of explosion, and provided the optimistic values of blasting parameters. The stress intensity factor and velocity of crack propagation were measured through dynamic caustics measuring system.展开更多
为解决铁路隧道机械化施工过程中设备选型、进度模拟及工况适应性分析等问题,利用达索公司3DEXPERIENCE平台下的CATIA和DELMIA软件模块,紧密结合当前建筑信息模型(building information modeling,BIM)技术的研究热点,先期完成了不同深...为解决铁路隧道机械化施工过程中设备选型、进度模拟及工况适应性分析等问题,利用达索公司3DEXPERIENCE平台下的CATIA和DELMIA软件模块,紧密结合当前建筑信息模型(building information modeling,BIM)技术的研究热点,先期完成了不同深度等级(level of development,LOD)的地形地质三维模型及结构单元库的创建,随后开展了基于各工序的系列施工设备动作关系和工作行程设计,并对设备的选型、适应性及施工进度等关键要素进行了过程分析。结果表明:隧道建模阶段创建的各类结构单元BIM模型,可用于施工设备与工艺流程定义阶段产品、工艺与资源组合模型(product process resources,PPR)中施工工艺流程的创建与相应资源调配,进而实现隧道BIM场景下的成套设备机械化施工方案可视化表达,为施工单位面临类似作业模式的隧道工程提供参考借鉴。展开更多
基金financially supported by the National Natural Science Fund of China(Nos.51004003 and 51474009)Anhui Province Education Department Natural Science Fund Key Project of China(No.KJ2010A091)
文摘In order to solve the problems of top-coal inadequate destruction and large amounts of gas emission in mining extra thick and hard coal seam,this study investigated the pre-splitting for deep borehole blasting and gas pre-draining technologies on top coal.The mechanism of the technologies was systematically expounded based on hard top-coal cracks development obtained by numerical simulation and theoretical analysis.The results show that explosive blasting in the hard rock results in a large number of cracks and large displacement in the rock mass due to the effect of explosion stress.Meanwhile,the thick top-coal caves,and desorbing gas flows along the cracks improve gas extraction.Finally,the pre-splitting for deep borehole blasting and gas pre-draining technologies was applied in No.3802 working face of Shui Liandong Coal Mine,which increases monthly output in the face to 67.34 kt and the drained gas concentration to 86.2%.The drained gas average concentration from each borehole reaches 40%,and the effect is remarkable.
文摘The stress strength factor, length and opening degree of cracks around boreholes as well as movement regularity Of blockage with the smooth blasting by water coupling are calculated out according to the theories of fracture mechanics and explosion dynamics, and the relation between the pressure in holes and the change of hoIe volume is pointed out, thereby the distance between boreholes is worked out in this paper. For limestone, when uncoupling coefficient is 3,diameter of holes is 100 mm, the hole distance of water coupling smooth blasting is 2. 3 m. The result is consistent with practice.
文摘Blasting operation dissipates much of the blasting energy in crushing the rock at the borehole and the resulting cracks are randomly oriented. There is very little control of the fracture plane. In order to control the fracture plane, many methods have been applied. This paper discusses a new blasting method in which a high degree of fracture control can be achieved while minimizing the ground shock.
文摘The size distribution of fragmented rocks depends on not only the blasting standard but also the mechanical properties, joint system and crack density of rock mass. As, especially, the cracks in the rock mass are heavily developed at the limestone quarries in Japan, the joints and/or cracks in the rock mass have big impacts on the blasting effects such as the size of fragmented rocks. Therefore, if the joint system and/or crack density in the rock mass can be known and evaluated in quantity, the blasting operation can be done more effectively, efficiency and safety. However, the guideline for designing the appropriate blasting standard based on the rock mass condition such as mechanical properties, joint system and/or distribution of cracks, discontinuities, from the scientific point of view, has not been developed yet. Therefore, a series of blasting tests had been conducted in different mines and faces, geological conditions and blasting standards in order to know the impacts of each factor on the blasting effects. This paper summarizes the results of blasting tests and describes the impacts of rock mass conditions and blasting standard on the size of fragmented rocks.
文摘This paper theoretically analyzed and discussed the fractures’ initiation, propagation and arrest of grooved borehole blasting under the function of explosion, and provided the optimistic values of blasting parameters. The stress intensity factor and velocity of crack propagation were measured through dynamic caustics measuring system.
文摘为解决铁路隧道机械化施工过程中设备选型、进度模拟及工况适应性分析等问题,利用达索公司3DEXPERIENCE平台下的CATIA和DELMIA软件模块,紧密结合当前建筑信息模型(building information modeling,BIM)技术的研究热点,先期完成了不同深度等级(level of development,LOD)的地形地质三维模型及结构单元库的创建,随后开展了基于各工序的系列施工设备动作关系和工作行程设计,并对设备的选型、适应性及施工进度等关键要素进行了过程分析。结果表明:隧道建模阶段创建的各类结构单元BIM模型,可用于施工设备与工艺流程定义阶段产品、工艺与资源组合模型(product process resources,PPR)中施工工艺流程的创建与相应资源调配,进而实现隧道BIM场景下的成套设备机械化施工方案可视化表达,为施工单位面临类似作业模式的隧道工程提供参考借鉴。
