基于流固耦合的强富水粉细砂隧道围岩数值模拟及其结果应用

Numerical simulation of strong water-rich silty sand tunnel surrounding rock based on fluid-structure coupling and its application

摘要

为研究强富水弱胶结粉细砂半成岩隧道围岩稳定性问题，基于流固耦合理论，以王家寨隧道为例，分析隧道施工过程中的渗流场、位移场、应力场变化规律及初期支护受力特性。研究结果表明：(1)考虑耦合效应时，隧道拱顶下沉值最大达到了12.6 mm,洞身水平位移达到了4.07 mm;无论是否考虑流固耦合，围岩与初支接触应力分布特征相似；考虑流固耦合效应下围岩压力大于不考虑流固耦合效应下的围岩压力；(2)在隧道开挖的过程中，孔隙水压力云图大致呈漏斗状，掌子面附近孔隙水压力值等值线密集，渗流作用明显；(3)地下渗流向开挖面聚集，与隧道实际掘进开挖出现地下水、发生突涌现象较为吻合；(4)根据模拟隧道开挖后产生渗流、位移、应力计算结果，在后续隧道施工过程中采取相应的预防处治措施，确保了工程施工进度与安全。说明该方法模拟计算与分析富水隧道围岩的稳定性是可行的，为富水隧道围岩稳定性分析与预防处治提供一定的理论依据。

Abstract

In order to study the rock stability of semi-diagenetic tunnel in strong water-rich and weakly cemented fine sand, based on the fluid-solid coupling theory, taking the Wangjiazhai tunnel as an example, the seepage field, displacement field, stress field variation law and initial support stress characteristics during tunnel construction are analyzed. The result show that:(1) When considering the coupling effect, the maximum subsidence value of the tunnel vault reaches 12.6 mm, and the horizontal displacement of the tunnel body reaches 4.07 mm; regardless of whether the fluid-solid coupling is considered, the distribution characteristics of the contact stress between the surrounding rock and the initial support are similar; the pressure in the surrounding rock, taking into account the fluid-solid coupling effect, is greater than that without taking into account the fluid-solid coupling effect.(2) During tunnel excavation, the pore water pressure map is roughly funnel shaped. The contours of the pore water pressure values near the palm face are dense, with obvious seepage effects.(3) The simulation result show that the underground seepage gathers to the excavation surface, which is consistent with the occurrence of groundwater and inrush in the actual excavation of the tunnel.(4) According to the calculation result of seepage, displacement and stress after the excavation of the simulated tunnel, corresponding preventive measures are taken in the subsequent tunnel construction process to ensure the construction progress and safety of the project.It shows that it is feasible to simulate and analyze the stability of surrounding rock of water-rich tunnel by this method, which provides a theoretical basis for the stability analysis and preventive treatment of surrounding rock of water-rich tunnel.

关键词

流固耦合 / 富水隧道 / 软弱围岩 / 稳定性分析 / 数值模拟

Key words

fluid-solid coupling / water-rich tunnel / weak surrounding rock / stability analysis / numerical simulation

Author summay

刘 刚(1977—), 男, 高级工程师, 学士, 主要从事隧道施工项目管理工作。E-mail: [e-mail]