富水软岩隧道注浆圈减压作用的简化理论计算与流固耦合数值模拟

Simplified theoretical calculation and stress-seepage coupled numerical modeling on reduction of external water pressure of tunnel lining due to grouting and drainage in water-rich soft rock

摘要

为计算注浆圈对减小衬砌外水压力和降低衬砌内力的作用，提出一种简化理论方法，并进行流固耦合有限元模拟。基于计算分析可知：(1)当隧道排水流量不大[不大于4 m³/(d·m)]时，可以利用所提出的简化理论方法来计算注浆圈厚度增大和渗透系数降低对衬砌外水压力和内力的折减，误差一般不大于10%;(2)当隧道排水流量较大[大于4 m³/(d·m)]时，简化理论方法的计算结果仍然可以反映衬砌外水压力和内力随注浆圈厚度和渗透系数变化的规律，但在量值上可有10%或以上的误差；(3)如果隧道不排水，注浆圈就只能起到阻滞渗流的作用，无论怎样增大其厚度，无论怎样降低其渗透系数，衬砌外水压力和内力也不会因此而有所折减；(4)隧道排水流量越大，注浆圈厚度越大，注浆圈渗透系数越低，衬砌外水压力的减小和内力的降低就越明显，但注浆圈厚度增大与渗透系数减小到一定程度以后，减压降力的效果趋于平缓。

Abstract

A simplified theoretical method is proposed and stress-seepage coupled numerical modeling conducted to calculate the reduction effects of grouting zone thickness and hydraulic conductivity variations, under prescribed drainage condictions, on the external water pressure and internal forces of lining. The calculations reveal the following observations:(1)When the drainage flux is not so large, e.g. less than 4 m³/(d.m), the simplified theoretical method can be employed to calculate the reduction effects with less than 10% errors.(2)When the drainage flux is quite large, e.g. larger than 4 m³/(d·m), the simplified theoretical method can still correctly refelect the variation trends, but possibly with no smaller than 10% errors.(3)Only when there is drainage, can the grouting zone contribute to the reduction effects, otherwise it can only serve as an impediment to seepage.(4) Within certain limits, the larger the drainage flux, the larger the grouting zone thickness, and the smaller the grouting zone hydraulic conductivity, the more significant the reduction effects.

关键词

富水软岩 / 注浆圈 / 排水流量 / 衬砌外水压力 / 衬砌内力 / 简化理论计算 / 流固耦合数值模拟

Key words

water-rich soft rock mass / grouting zone / drainage flux / external water pressure on lining / internal force of lining / simplified theoretical calculation / stress-seepage coupled numerical modeling

Author summay

于晨昀 (1984—), 男, 正高级工程师, 硕士, 主要从事隧道工程勘察设计与研究工作。E-mail: [e-mail]

基金资助

中国中铁股份有限公司项目(2020-引导-56)

中铁工程设计咨询集团有限公司项目(研2020-23)