围岩荷载的确定是进行隧道工程衬砌结构设计的关键.现行铁路隧道规范中深埋隧道围岩荷载计算公式是根据单线铁路隧道施工塌方的调查统计资料建立起来的统计经验公式,多年来,对于指导单、双线铁路隧道的结构设计起到至关重要的作用,但用于指导当前三线,特别是四线铁路隧道时,就显得无能为力了.提出一种合理的适合于三线、四线甚至更大跨度的铁路隧道的围岩荷载计算方法,提出考虑围岩变形全过程的"统一围岩压力曲线",并基于贵昆铁路六盘水至沾益段增建二线上的乌蒙山2号四线车站大跨度隧道,开展现场试验,对围岩压力进行监控量测,结合统一围岩压力曲线,提出竖向围岩压力计算公式q=Kyha.%It is a key to determine the surrounding rock pressure in the design of the tunnel. The calculation formula of surrounding rock pressure of deep depth railway tunnel in China is an empirical formula established by statistical data based on the construction of a large number of tunnel collapse events. It plays a very important role in the structural design of single and double-track tunnels, but it could hardly possible to guide the design of the three-track, especially the four-track railway tunnels. Therefore,it is urgent to formulate a method to calculate the surrounding rock pressure of multi-track tunnel. The theory of"unified pressure curve of surrounding rock"is proposed. Based on the construction of No. 2 Wumengshan large-span four-track railway-station tunnel, field experiments are carried out to test surrounding rock pressure. Combined with the theory of"unified pressure curve of surrounding rock", this paper puts forward the calculation formula of q=Kyhafor vertical surrounding rock pressure.
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