超大断面黄土公路隧道围岩压力计算方法分析

Calculation Method for Surrounding Rock Pressure of a Loess Highway Tunnel with an Extra-Large Section

文章基于唐家塬超大断面黄土隧道工程实例,采用常用的五种围岩压力计算方法分别计算了围岩压力,并与实测值进行了对比分析,得出了现场实测垂直压力与太沙基理论计算结果基本吻合的结论。在此基础上提出了太沙基理论侧压力系数修正方法,并推荐采用修正后的太沙基理论作为唐家塬隧道的围岩压力计算方法。针对现有隧道深、浅埋界定标准的问题,提出了以中心线土体侧压力系数变化规律为依据的深、浅埋界定数值模拟方法。由此认为,唐家塬隧道为浅埋隧道,隧道深浅埋界限为90 m。

Using the construction of the Tangjiayuan tunnel in loess with an extra-large section as an example,the surrounding rock pressure is calculated by five common methods, of which the results from the Terzaghi theory-based method were very consistent with the measured data. A correction method is put forward regarding the lateral pressure coefficient, and is recommended for application to the Tangjiayuan tunnel. Furthermore, in light of the definition criterion between the shallow- and deep-buried tunnels, a simulation method is also proposed for determining the boundary of the shallow and deep depths based on the variation rule of the lateral pressure coefficient of the soil body on the centerline, the Tangjiayuan tunnel is considered to be shallow-buried,with a boundary of 90 m.