摘要
当地下水从衬砌接缝或裂缝进入隧道时,土体中的细颗粒会在渗流作用下从土体骨架上脱落流入隧道内,这种现象被称作内部侵蚀。然而,当前对隧道渗漏问题的研究中,并没有考虑土体细颗粒流失对隧道结构及周围土体的影响。因此,在连续介质力学框架下开发了一个两相四组分模型,以描述内部侵蚀过程及其引起的土体孔隙度、细颗粒含量及渗透系数等变化;结合一个与颗粒级配相关的非关联临界状态弹塑性本构模型,将细颗粒含量的变化与土体孔隙率、密实度及临界状态线的空间位置相关联以考虑内部侵蚀对土体力学性质的影响。研究结果表明,本模型可以描述隧道渗漏引起的侵蚀区域的时空演化全过程,而基于孔压降低的分析方法会低估渗漏引起的衬砌内力和地层变化。此外,研究还发现三维条件是准确模拟土体内部侵蚀过程的一个重要因素。
When groundwater leaks into the tunnel from damaged joints or cracks of the linings,fine particles could be pulled off by seepage force and transported throughout the soil matrix into the tunnel.Currently,very limited attention has been paid to the effect of the loss of fine particles induced by the water leakage,namely the internal erosion.In this study,the evolution of soil porosity,gradation,seepage flow,the induced ground movement and lining stress change due to tunnel leakage has been numerically investigated using a novel coupled hydro-mechanical approach formulated within the continuous porous medium framework.A critical state based constitutive model considering the influence of the fines content has been implemented for modelling the mechanical consequences of internal erosion.The numerical results show the spatial and temporal evolution of the eroded zone and the hydro-mechanical response of the tunnel and its surroundings.The results indicate that the commonly used pore pressure reduction-based method without considering internal erosion will under-estimate the leakage induced lining stress change and ground movement.Moreover,the influences of three-dimensional condition are highlighted.
作者
刘映晶
杨杰
尹振宇
LIU Ying-jing;YANG Jie;YIN Zhen-yu(Zhongtian Construction Group Co.,Ltd.,Hangzhou,Zhejiang 310009,China;Department of Civil and Environmental Engineering,The Hong Kong Polytechnic University,Hong Kong,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2022年第5期1383-1390,1400,共9页
Rock and Soil Mechanics
基金
香港研究资助委员会GRF项目(No.15217220)。
关键词
隧道
粉砂
细颗粒
有限元
内部侵蚀
渗流
tunnel
silty sand
fine particles
finite element method
internal erosion
seepage
