摘要
压气法盾构施工技术在水下隧道修建中具有显著优点,但缺乏理论分析模型。基于质量守恒和理想气态方程,建立了盾构土仓内气压与压缩气体进出流量关系的理论模型,通过掌子面动态气压边界,将其与考虑气-液两相流的围岩数值模型耦合,形成盾构仓内气压与围岩气-液两相流相互作用模型。基于现场数据验证了模型的有效性,分析了停机情况下压气法土仓压力影响因素,主要结论如下:土仓压力随压缩空气的注入先增大后降低并趋于平稳,空气注入速率增大,土仓压力峰值和平稳值相应增大。土仓内压缩空气可减小土仓压力波动速率和幅度,空气体积越大,效果越好;压气法宜在渗透系数较小的地层中使用,地层渗透系数越大,对压缩空气的约束能力越小,甚至出现贯通至地表的空气排出通道。渗透系数较大地层中,突然停止空气注入,可能导致土仓压力快速下降和地下水涌入,危及施工安全。
The compressed air method in shield tunneling exhibits significant advantages in underwater tunnel construction,yet it lacks a comprehensive theoretical analysis model.A theoretical model for the relationship between air pressure in the shield chamber and the inflow and outflow of compressed air is firstly established,based on the principles of mass conservation and the ideal gas law.A dynamic air pressure boundary at the tunnel face is used to integrate the theoretical model with a numerical model of the surrounding rock that considers gas-liquid two-phase flow.The model is validated through field data.Analysis of key factors affecting chamber pressure during shield shutdown reveals that chamber pressure initially increases,then decreases,and eventually stabilizes upon compressed air injection.Higher air injection rates lead to increased peak and stable chamber pressures.Compressed air within the chamber reduces the rate and amplitude of pressure fluctuations,with a larger volume of air amplifying this effect.The compressed air method is best suited for strata with low permeability.As the permeability coefficient of the stratum increases,the ability of stratum to contain compressed air decreases,leading to the formation of air discharge channels extending to the ground surface.In strata with higher permeability coefficients,abruptly halting air injection can cause a rapid drop in chamber pressure and groundwater influx,threatening construction safety.
作者
黄继辉
秦世康
赵昱
陈景煦
张浩
HUANG Ji-hui;QIN Shi-kang;ZHAO Yu;CHEN Jing-xu;ZHANG Hao(School of Rail Transit,Fujian Chuanzheng Communications College,Fuzhou,Fujian 350007,China;Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;National Key Laboratory of Green and Long-Life Road Engineering in Extreme Environment,Shenzhen University,Shenzhen,Guangdong 518061,China;CSCEC Strait Construction and Development Co.,Ltd.,Fuzhou,Fujian 350015,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第12期3555-3565,共11页
Rock and Soil Mechanics
基金
福建省自然科学基金面上项目(No.2022J01390)
福建省中青年教师教育科研项目(No.JZ230073)
福建船政交通职业学院校科教发展基金(No.Z202206004)。
关键词
盾构隧道
压气法
两相渗流
数值模拟
shield tunnel
compressed air method
two-phase flow
numerical simulation
