Undercrossing tunnels are frequently constructed by the shield-driven method in metro projects.Shield tunneling affects the existing tunnel inevitably.

摘要在地铁程中，常采用盾法修建正交下穿隧道，新隧道不可避免地对既有隧道产生影响。

The technical measures and structure,applied principles of blastproof of ventilation shaft at excavating face,specific operational method and prospective effect are described.

介绍了作面防炮崩风筒主要技术措施及技术结、应用原理、采用这项技术具体操作方法及预期效果。

Give priority to develop and manufacture full-face excavator, large-tonnage hydraulic excavator, heavy-tonnage loader, autocrane series, medium and small tonnage and multifunctional loaders.

重点开发生产全断面机、大型液压挖机、大吨位轮式装载机、系列汽车起重机以及静液压式中小吨位和多功能装载机。