列车振动作用下盾构隧道周边土体渗流侵蚀的离散元-孔隙网络耦合模拟  

Numerical Analysis of Seepage Erosion in Surrounding Soil of Shield Tunnel under Train Vibration Loads with DEM-PNM Method

作　　者：陈思睿 张冬梅[1,2] 谢小创[1] CHEN Sirui;ZHANG Dongmei;XIE Xiaochuang(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092;State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092)

机构地区：[1]同济大学土木工程学院地下建筑与工程系,上海200092 [2]同济大学土木工程防灾减灾全国重点实验室,上海200092

出　　处：《现代隧道技术》2024年第S01期466-473,共8页Modern Tunnelling Technology

基　　金：国家自然科学基金(52238010,52408436);国家重点研发计划课题(2022YFC3800905);上海市白玉兰人才计划浦江项目(23PJD104)

摘　　要：对于建在砂土层的盾构隧道,渗漏水会携带细小土颗粒进入隧道,引发渗流侵蚀。列车振动显著影响隧道周围水和土体的运动特性,然而振动对隧道周边渗流侵蚀的影响尚不清楚。文章采用离散元(DEM)和孔隙网络(PNM)耦合方法,研究了间断级配砂土中列车振动对渗流侵蚀的影响。首先,建立了单元尺度的土体试样模型,通过底部的流失缝模拟隧道接缝张开情况,在振动和静态条件下分别进行侵蚀。其中,选择了频率为30 Hz、振幅为0.02 mm的典型隧道管片振动模式并通过模型底部边界施加。结果表明,与静态情况相比,振动会导致更大的质量损失和更远的细颗粒迁移距离,还会阻碍细颗粒与粗颗粒间土拱的形成,从而降低土体的抗侵蚀能力。此外,振动还会导致孔喉面积频繁变化,加剧颗粒的重分布,增加细颗粒流失的可能性。For tunnels built in silty sand,leakage can carry fine particles into the tunnels,leading to suffusion.The motion of water and sand particles around the tunnel is greatly influenced by train vibrations,however,the effect of vibration on suffusion is still unclear.In this study,a coupled discrete element method(DEM)and pore network method(PNM)approach is employed to investigate the effects of vibration on suffusion in gap-graded soils from a microscopic perspective.A cell-scale sample is modeled to undergo suffusion under both vibrating and static conditions.A typical tunnel segment vibration with a frequency of 30 Hz and an amplitude of 0.02 mm is selected and applied through the displacement of the bottom plate.The results indicate that vibration induces a significant increase in mass loss and fne particle migration compared to the static case.It can also deteriorate the soil's erosion resistance by preventing the formation of soil arches.Moreover,vibration causes a frequent change in pore throat area,which accelerates particle redistribution and increases the likelihood of fine particles loss.The findings from this study reveal the mechanism of internal erosion around shield tunnels subjected to train vibration loads,which provides an important reference for disaster prevention during tunnel operation.

关 键 词：盾构隧道 渗流侵蚀 列车振动 数值模拟 离散元-孔隙网络耦合 

分 类 号：U457[建筑科学—桥梁与隧道工程] U270.11[交通运输工程—道路与铁道工程]