岩体隧道拱顶稳定性数值分析

Numerical Analysis on Vault Stability of Rock Tunnel

岩体隧道的侧压力系数是评价围岩拱顶稳定性的重要参数。该文结合工程实例,运用有限差分软件FLAC3D建立隧道数值模型,对11种侧压力系数作用下直墙圆拱隧道拱顶的稳定性进行数值模拟,分析围岩的侧压力系数λ∈[0,1]变化过程中拱顶岩体的应力场与位移场的变化规律。结果表明,当侧压力系数λ〈0.15时,拱顶围岩的最大主应力和最小主应力都是拉应力;当0.15〈λ〈0.38时,拱顶围岩的最大主应力为压应力而最小主应力为拉应力;当λ〉0.38时,拱顶围岩的最大主应力和最小主应力都是压应力。围岩的侧压力系数λ由0-1变化时,拱顶围岩分别经历了双向受拉,拉压共存和双向受压3种状态,拱顶最终沉降值随着围岩的侧压力系数λ的增大而减小。

The lateral pressure coefficient of rock tunnel is an important factor to evaluate the vault stability of surrounding rocks.Here, combining with the engineering examples and by using the finite difference software FLAC3D to set up the numerical model,11 stress and displacement results about the lateral pressure coefficient are modelled numerically,and the movement process of stress field and displacement field of the lateral pressure coefficient of surrounding rocks from 0-1 is analyzed.The results show that when the lateral pressure coefficient of surrounding rocks is from 0-1,the surrounding rock＇s vault is experienced by three states,such as the two-way tension,tension-compression coexistence and two-way compression,and the settlement of the vault decreases along with the increasing of the lateral pressure coefficient of surrounding rocks.