Designing reliable yielding support system to mitigate the effect of the kinetic energy in burst-prone conditions in mining and tunneling excavations is one of the challenges for geotechnical engineers. A combination ...Designing reliable yielding support system to mitigate the effect of the kinetic energy in burst-prone conditions in mining and tunneling excavations is one of the challenges for geotechnical engineers. A combination of the support elements can be used to increase rock strength and minimise the displacement of unstable rock mass. It is important to understand how the support system works to ensure the stability of underground excavations. Cable bolts have been commonly used as an effective underground support system and an element of reinforcement to improve rock stability. Cable bolts are usually considered to be subjected to static loads under relatively low stress environments, however, in burst-prone conditions, they might be subjected to dynamic loads. Cable bolts as well as other support elements are used in burst-prone conditions to absorb the kinetic energy of the removed rock to avoid sudden and violent failures. This paper develops numerical and a novel analytical simulation technique for cable bolts to assess their structural behaviour under static and dynamic loading conditions. The numerical and analytical models are then validated against experimental observations reported in the literature, which demonstrates the reliability of the proposed models.展开更多
In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of g...In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of gob-side entry technology. The concrete has a long initial setting time and a low initial strength. So it is difficult to control the surrounding rock. In this paper, we analyze the effect of using roadside cable to reinforce supporting in gob-side entry surrounding rock controlling based on elas-tic-plastic and material mechanics knowledge. And then we propose a scheme that cable is used to reinforce roadside supporting and a single hydraulic prop is used as the temporary supporting in gob side. Using the numerical simulation software FLAC2D, we numerically simulated supporting scheme. Results of both the 2D modeling and the industrial test on No.3117 face in Jingang Mine prove that the scheme is feasible. The results show that the technology of protecting the roadway in gob-entry retained efficiently make up the deficiency of roadside packing with ordinary concrete, effectively control the roof strata and acquire a good result of retaining roadway.展开更多
随着电力电缆在远距离输电系统的大力发展,电缆支架大规模应用,输电电压等级逐渐增加,电缆输送容量越来越大,成本低廉的普通钢支架涡流损耗不能忽略,讨论了电缆支架涡流损耗的计算原理及方法,针对220 k V高压电缆,建立有限元模型,从载...随着电力电缆在远距离输电系统的大力发展,电缆支架大规模应用,输电电压等级逐渐增加,电缆输送容量越来越大,成本低廉的普通钢支架涡流损耗不能忽略,讨论了电缆支架涡流损耗的计算原理及方法,针对220 k V高压电缆,建立有限元模型,从载流量、电缆与支架间距离、电缆排列方式、电缆支架材料四个维度考虑,定量的计算了各工况的电缆支架涡流损耗情况,根据计算结果,得出各变量对电缆支架涡流损耗的影响规律,并提出几种降低电缆支架涡流损耗方案。展开更多
文摘Designing reliable yielding support system to mitigate the effect of the kinetic energy in burst-prone conditions in mining and tunneling excavations is one of the challenges for geotechnical engineers. A combination of the support elements can be used to increase rock strength and minimise the displacement of unstable rock mass. It is important to understand how the support system works to ensure the stability of underground excavations. Cable bolts have been commonly used as an effective underground support system and an element of reinforcement to improve rock stability. Cable bolts are usually considered to be subjected to static loads under relatively low stress environments, however, in burst-prone conditions, they might be subjected to dynamic loads. Cable bolts as well as other support elements are used in burst-prone conditions to absorb the kinetic energy of the removed rock to avoid sudden and violent failures. This paper develops numerical and a novel analytical simulation technique for cable bolts to assess their structural behaviour under static and dynamic loading conditions. The numerical and analytical models are then validated against experimental observations reported in the literature, which demonstrates the reliability of the proposed models.
基金support from the National Nature Science Foundation of China (No50874124)
文摘In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of gob-side entry technology. The concrete has a long initial setting time and a low initial strength. So it is difficult to control the surrounding rock. In this paper, we analyze the effect of using roadside cable to reinforce supporting in gob-side entry surrounding rock controlling based on elas-tic-plastic and material mechanics knowledge. And then we propose a scheme that cable is used to reinforce roadside supporting and a single hydraulic prop is used as the temporary supporting in gob side. Using the numerical simulation software FLAC2D, we numerically simulated supporting scheme. Results of both the 2D modeling and the industrial test on No.3117 face in Jingang Mine prove that the scheme is feasible. The results show that the technology of protecting the roadway in gob-entry retained efficiently make up the deficiency of roadside packing with ordinary concrete, effectively control the roof strata and acquire a good result of retaining roadway.
文摘随着电力电缆在远距离输电系统的大力发展,电缆支架大规模应用,输电电压等级逐渐增加,电缆输送容量越来越大,成本低廉的普通钢支架涡流损耗不能忽略,讨论了电缆支架涡流损耗的计算原理及方法,针对220 k V高压电缆,建立有限元模型,从载流量、电缆与支架间距离、电缆排列方式、电缆支架材料四个维度考虑,定量的计算了各工况的电缆支架涡流损耗情况,根据计算结果,得出各变量对电缆支架涡流损耗的影响规律,并提出几种降低电缆支架涡流损耗方案。
