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当前隧道相关规范中提供的计算隧道上方土体对衬砌地震作用力的方法,仍采用静压力拱的高度来确定衬砌上方土体的地震作用高度,其准确性有待确定。本文采用解析计算与有限元计算对比分析的方法,通过研究隧道上方竖向应力在地震前后沿深度的变化,来确定隧道上方土体的地震作用高度HP,给出了考虑隧道跨度、围岩级别、隧道结构形状及埋深等因素的隧道上方土体对衬砌地震作用高度的计算公式,确定了衬砌上的作用力,明确了其作用方式,并验证了其适用性。研究结果表明:解析计算和有限元计算所得结果沿隧道衬砌的分布规律一致;隧道埋深较小时,隧道规范计算出的HP偏大;埋深较大时,隧道规范计算出的HP偏小,采用该方法确定隧道上方土体地震作用高度HP是可行的;衬砌上的作用力以切向力形式分布在衬砌的上半拱。研究结果可为隧道抗震计算及设计提供参考。
The method of calculating the soil-to-lining seismic force above the tunnel provided in the current tunnel-related codes still uses the height of the static pressure arch to determine the seismic action height of the soil above the lining, and its accuracy needs to be determined. In this paper, by means of comparative analysis of analytical calculation and finite element calculation, the vertical height of the tunnel above the earthquake before and after the earthquake along the depth changes to determine the seismic action of the soil above the tunnel height HP, given the consideration of the tunnel span, , The shape of the tunnel structure and the depth of the tunnel and other factors above the tunnel lining soil height of the earthquake action formula to determine the force on the lining to clarify its mode of operation and verify its applicability. The results show that the results of analytical calculation and finite element analysis are consistent with the distribution of the tunnel lining. When the tunnel depth is small, the HP calculated by the tunnel gauge is larger. When the depth is larger, the HP calculated by the tunnel gauge is smaller, It is feasible to use this method to determine the seismic action height HP of the soil above the tunnel. The force acting on the lining is distributed in the upper half-arch of the lining by the tangential force. The results can provide reference for seismic calculation and design of tunnels.