有限元方法在节理岩体隧洞力学分析中的应用

Numerical Study on Tunnel Mechanics in Jointed Rock Mass with Finite Element Method

在节理岩体中,隧洞的力学性质主要取决于节理的性质,其最常用的数值分析方法是有限元分析方法。本文结合盖下坝引水隧洞,考虑节理倾角、节理间距和水平测压力系数,建立有限元分析模型。计算结果表明,隧洞围岩塑性扩展区和变形沿节理方向大致呈对称分布,且隧洞围岩塑性的区范围与古德曼(Goodman)图解法的判别基本一致。节理倾角和间距对隧洞围岩力学特性有明显影响,但构造应力才是影响隧洞围岩稳定性的主导性因素。

Tunnel mechanics mainly depend on joints properties in layered and jointed rock mass,and most of the present methods adopted in numerical analysis are distinct element method.Combining to the Gaixiaba tunnel,considering the jointed properties such as dip angles,distances and lateral pressure coefficient,the finite element models are made in this paper.Results show that the plastic zone and total displacement presented a symmetric distribution with the axial of joints dip,and the plastic zone is very similar to the results suggested by Goodman.The dip angles,distances of joints and lateral pressure coefficient have significant effect on the tunnel mechanics.