山区高速铁路隧道间桥隧连接结构探讨

摘要

研究目的:根据调整后的中长期铁路网规划,我国将建设1.6万千米以上的客运专线,而位于中西部山区的高速铁路需修建大量的桥隧工程,且大多桥隧相连、成群分布,高速列车运行对安全度要求极高,乘客舒适度也是必须考虑的问题,当两隧道间因地形条件及线路走向限制,明线间隔距离很短时,有必要对是否在桥上部设置连接防护结构及其结构型式进行深入研究,确保运营安全和提高乘客舒适度.研究结论:(1)两隧道洞口间距大于250 m时可将隧道看成独立隧道.小于250 m时,单列车通过隧道群中的每一座隧道时引起的车内压力波动相互间有影响,之间加设连接结构可降低车内3 s内最大压力变化值,有利于改善车内舒适度环境,可缓解列车频繁进出隧道,“黑洞”和“白洞”效应引起的乘客视觉疲劳问题.(2)隧道洞口坡面陡峻,存在危岩落石危害时,在采取坡面防护措施的基础上,设置连接防护结构可以有效防止小粒径落石对运营安全的威胁.(3)连接防护结构采用柔性防护网钢结构,具有安全可靠、经济适用的优点,在进行落石冲击试验后可以用于实际工程.%Research purposes: According to the medium and long - term railway network planning of China, the sixteen thousands kilometers of passenger dedicated rail line will be built. So lots of bridges and tunnels will be built for the high - speed railway in the mountain areas of the Midwest of China, with bridge connecting with tunnel and forming group. The high - speed train running on such railway requires high safety and the passenger needs ride comfortableness. So it is necessary to study whether the safeguard structure is installed on the bridge or not and what kind of the safeguard structure should be used when the open track between tunnel portals is short due to the limitations of thetopographic condition and the railway alignment.Research conclusions: (1) When the distance between the adjacent portals of two tunnels is more than 250 m, the two tunnels may be considered as independent ones. When it is less than 250 m, the pressure fluctuation produced by a train passing through the tunnels will be interacted. The variation of maximum pressure in 3 s can be reduced by the safeguard structure. In this way, the visual fatigue of passengers caused by the " black tunnel" and " white tunnel" due to frequently passing in and out tunnels of train can be relieved. (2) Using safeguard structure along with the safeguard protection on the side slope,the threat to the operation safety from the falling stone with small grain size can be effectively protected when the slope surface at the tunnel portal is high and precipitous. (3 ) The flexible net steel safeguard structure can beused for the connecting safeguard structure with the features of high safety, reliability and money saving and it can beused in the actual engineering after doing the rock falling impact test.