隧底与围岩接触面积对接触压力影响的有限元分析

隧底脱空将影响隧底围岩与仰拱之间的接触压力大小与分布,而列车轴重的增加将放大这种影响。为获得重载条件下隧底结构与围岩之间的接触压力受接触面积影响的因素与作用规律,运用数值模拟对隧底不同接触面积下的接触压力进行计算分析。结果表明:围岩级别、隧底和围岩接触面积的大小对隧底接触压力影响显著。表现为:围岩级别越高、列车轴重越大,隧底脱空对接触压力的影响越显著;接触压力与脱空率之间呈近似线性相关;在脱空率相同时,脱空位置离拱底越近,接触压力越大,其最大、最小值分别出现在拱底以及仰拱与拱脚连接处。

Finite Element Analysis of Effect of Contact Area of Tunnel Bottom and Surrounding Rock on Contact Pressure

For separation from tunnel bottom may affect the distribution and the size of contact pressure between the inverted arch and the surrounding rock, and the increase of train axle load will amplify this influence. To study the influence of the contact area on the contact pressure between the inverted arch and the surrounding rock and its action law, computational analysis is performed for the contact pressure at different contact area at the tunnel bottom by numerical simulation.. The analysis reveals that surrounding rock grade and the size of contact area of the tunnel bottom and the surrounding rock has significant impact on the contact pressure at the tunnel bottom:the greater the rock grade and the train axle load, the more significant the effect of the separation for the contact pressure. there is an approximately linear correlation between the contact pressure and the separation from tunnel bottom; at the same rate of the separation, the nearer separation position is from the arch,the greater the contact pressure is, and the maximum and minimum contact pressure is respectively located in the arch bottom and the junction between the inverted arch and arch bottom.