神华煤炭集团大柳塔煤矿单巷长距离快速掘进系统因通风系统不合理造成工作面除尘效果不佳,掘进机司机工位处粉尘浓度超标。针对这一问题,提出一种基于风筒吊挂动态延伸技术的解决方案。根据恒力液压绞车钢丝绳预紧风筒吊挂装置的结构与...神华煤炭集团大柳塔煤矿单巷长距离快速掘进系统因通风系统不合理造成工作面除尘效果不佳,掘进机司机工位处粉尘浓度超标。针对这一问题,提出一种基于风筒吊挂动态延伸技术的解决方案。根据恒力液压绞车钢丝绳预紧风筒吊挂装置的结构与工作原理,建立风筒吊挂受力数学模型,计算得钢丝绳最小破断拉力F_0为150 k N,安全系数为2.73。考虑防风筒吸瘪、绞车夹绳等关键技术,设计风筒吊挂工艺。现场实验表明,该装置能够适应快速掘进系统,有效改善掘进工作面的通风状况,降低掘进机司机工位处粉尘浓度达50%以上。展开更多
We studied the dynamic fracture mechanical behavior of rock under different impact rates. The fracture experiment was a three-point bending beam subjected to different impact loads monitored using the reflected causti...We studied the dynamic fracture mechanical behavior of rock under different impact rates. The fracture experiment was a three-point bending beam subjected to different impact loads monitored using the reflected caustics method. The mechanical parameters for fracture of the three-poim bending beam specimen under impact load are analyzed. The mechanism of crack propagation is discussed. Experimental results show that the dynamic stress intensity factor increases before crack initiation. When the dynamic stress intensity factor reaches its maximum value the crack starts to develop. After crack initiation the dynamic stress intensity factor decreases rapidly and oscillates. As the impact rate increases the cracks initiate earlier, the maximum value of crack growth velocity becomes smaller and the values of dynamic stress intensity factor also vary less during crack propagation. The results provide a theoretical basis for the study of rock dynamic fracture.展开更多
文摘神华煤炭集团大柳塔煤矿单巷长距离快速掘进系统因通风系统不合理造成工作面除尘效果不佳,掘进机司机工位处粉尘浓度超标。针对这一问题,提出一种基于风筒吊挂动态延伸技术的解决方案。根据恒力液压绞车钢丝绳预紧风筒吊挂装置的结构与工作原理,建立风筒吊挂受力数学模型,计算得钢丝绳最小破断拉力F_0为150 k N,安全系数为2.73。考虑防风筒吸瘪、绞车夹绳等关键技术,设计风筒吊挂工艺。现场实验表明,该装置能够适应快速掘进系统,有效改善掘进工作面的通风状况,降低掘进机司机工位处粉尘浓度达50%以上。
基金the support of the National Natural Science Foundation of China (Grant No.50774086 and 50874109)
文摘We studied the dynamic fracture mechanical behavior of rock under different impact rates. The fracture experiment was a three-point bending beam subjected to different impact loads monitored using the reflected caustics method. The mechanical parameters for fracture of the three-poim bending beam specimen under impact load are analyzed. The mechanism of crack propagation is discussed. Experimental results show that the dynamic stress intensity factor increases before crack initiation. When the dynamic stress intensity factor reaches its maximum value the crack starts to develop. After crack initiation the dynamic stress intensity factor decreases rapidly and oscillates. As the impact rate increases the cracks initiate earlier, the maximum value of crack growth velocity becomes smaller and the values of dynamic stress intensity factor also vary less during crack propagation. The results provide a theoretical basis for the study of rock dynamic fracture.
