含厚层软弱夹层硬质围岩的变形破坏特性

以某隧道为背景,通过地质条件分析并结合FLAC3D数值模拟手段,采用对比含有厚层软弱夹层和不含软弱夹层的2个不同模型的方法,从地应力变化、塑性区开展、变形、下覆岩体受压和位移等角度分析了含厚层软弱夹层硬质围岩的变形破坏特性。发现对于含厚层软弱夹层和不含软弱夹层的这2个不同模型,地应力的差别较小,但都为不含节理的岩体的0.5倍或更小,因此认为节理是影响含厚层软弱夹层硬质围岩变性破坏的因素之一;而2个模型在塑性区开展、变形量、下覆岩体受压和位移等方面差别较大,因此认为厚层软弱夹层对硬质围岩的变形破坏起着显著作用。同时通过创建三维模型采用分步开挖的方法,模拟了含厚层软弱夹层硬质围岩的变形破坏过程,分析认为其具有隐蔽性和发生时间不确定性的特点。研究结果可为类似地质情况的隧道建设提供参考。

Deformation and Damage Characteristics of Hard Rock Mass with Thick Weak Interlayer

Based on the geological investigation,the deformation and damage characteristics of hard rock mass with thick weak interlayer of a typical tunnel is simulated using FLAC3D.Two models with and without weak interlayer are adopted to analyze the characteristics of ground stress,plastic zone,deformation of the rock mass and the displacement and pressure of underlying rock mass.The results show that stress distribution of the two models are almost the same which are 30%～50% of normal rock mass,but the plastic zone,the strain,the interface normal stress and the displacement of underlying rock mass are quite different.So it can be concluded that the joint and the weak interlayer both contribute to the deformation and damage of rock mass.At the same time,the construction and deformation process of a tunnel are si-mulated using a 3d model.The result shows that the deformation and damage have the characteristics of concealment and temporal uncertainty.This study can provide reference to other tunnels with similar geological conditions.