富水巷道流固耦合效应FLAC-3D模拟

Simulation of fluid-solid interaction effect in rich water tunnel based on FLAC-3D

为探索富水岩层中开挖拱形巷道的稳定性问题,基于流固耦合分析理论,运用FLAC-3D中的等效连续介质渗流模型及FISH语言实现了巷道开挖后流固耦合效应的模拟,探讨了渗流场及场内流动矢量的分布特征,针对围岩塑性区、应力场及变形规律与非流固耦合进行对比分析.在流固耦合模式下,研究了开挖步长对孔隙水压力和竖向位移的影响规律.结果表明:流固耦合模式下,巷道围岩中形成了一个类似降水漏斗的形状,在巷道拱脚处流动矢量分布密集而且数值较大,随着开挖步长的增大,巷道拱顶孔隙水压力及竖向位移则有所减小.与非流固耦合相比,围岩塑性区范围和剪切带尺寸均有所增大,竖向总应力相对增大了10%.

In order to analyze the stability of the arched tunnel after excavation in rich water rock, based on fluid-structure interaction theory, the simulation of fluid-structure interaction effect is realized by use of FISH language and equivalent continuous media seepage model in FLAC-3D. The distributions of seepage field and flow vector are elaborated, and a comparison of plastic zone, stress field and deformation of surrounding rock between consider fluid-structure interaction and out of considering fluid-structure interaction is made. By considering fluid-structure interaction, the influences of excavation steps on pore pressure and displacements are analyzed. Result shows that there is a reinforced area in surrounding rock, and flow vector is intensive and larger in tunnel arch springing. With the increase of excavation steps, pore pressure and vertical displacement in tunnel vault increase obviously. Comparing with out of considering fluid-structure interaction, the range of plastic zone and the length of shear bands are bigger, and the total vertical stress reduces 10% relatively in considering fluid-structure interaction.