连拱隧道中墙受力研究

采用有限元数值计算方法,进行连拱隧道中墙的受力分析研究。结果表明:在中墙一定的情况下,两侧主洞的施工顺序、支护情况、应力释放系数对中墙的最终受力影响不大;中墙轴力随中导坑的扩大而减小,其中中导坑宽度影响较大;中墙应力随中墙厚度的增加而减小,但超过2m以后,减小幅度变得不明显,说明一味采用增加中墙厚度来确保中墙安全的做法是不合理的;在一定范围内,随着埋深的增加中墙受力增大;当埋深较大时,在中墙顶部预留适当的变形量,可以有效减小中墙承受的形变压力。

Mechanical Behavior of Middle Wall in Continuous Arch Tunnel

Analyze and study the mechanical behavior of middle wall by using FEM. When the middle wall keeps invariable, the influence of construction sequence, support measure and stress release coefficient of two side tunnels on its internal force isn't great. The axial force of middle wall decreases with the increase of the middle heading, the width of middle heading influences greater. The axial force of middle wall increases with the increase of thickness of the middle wall. Whereas the stress decreases constantly, but the reduce range decreases after the thickness of middle wall reaches 2 meters, the reduce range is not obvious. So singly thickening middle wall to ensure middle wall is not reasonable. In the range of some depth, the axial force of middle wall increases with the increase of buried depth. When buried depth is greater, leaving proper deformation space above the middle wall can effectively reduce the deformation pressure supported by the middle wall.