摘要
下部地层注浆是盾构隧道过大沉降的常用治理措施。结构性软黏土地层中注浆引起的超孔压在注浆后持续消散,导致隧道抬升后因地层固结而发生沉降,进而降低隧道抬升效率。为预测下方地层注浆引起的盾构隧道纵向变形,提出了考虑土体结构性的盾构隧道底部注浆抬升量—沉降量两阶段计算方法。应用于宁波地铁2号线注浆抬升案例,隧道抬升效率计算值约51%,与同为软黏土地层的上海地铁2号线某区间盾构隧道实测抬升效率非常接近。此外,针对注浆参数、地层参数与隧道参数开展了参数分析,结果表明:隧道最终抬升量及抬升效率与土体基床系数、注浆体积呈正相关,与地层屈服应力成负相关;随埋深比增大,注浆区域隧道最终抬升量减小,而抬升效率变化甚微。计算方法可以为软黏土地层运营盾构隧道注浆抬升设计提供理论支撑。
Grouting in the underlying strata is a common remedial measure for the excessive settlement of shield tunnels.In the case of structured soft clays,the grouting process induces dissipation of the excess pore pressure in the surrounding strata,which leads to settlement of the tunnel after the grouting process and subsequently reduces the uplift efficiency.In order to predict the longitudinal deformation of shield tunnels caused by grouting in the underlying strata,a two-stage method for calculating the uplift and settlement of shield tunnels is proposed considering the structural characteristics of the soil.It is applied to a grouting uplift case in Ningbo Metro Line 2,and the calculated uplift efficiency of the tunnel is approximately 51%,which is close to the measured uplift efficiency of an interval of Shanghai Metro Line 2 in soft clayey ground.Furthermore,the parametric study is conducted,considering the parameters of grouting,strata and tunnel.The results indicate that the final uplift settlement and uplift efficiency of the tunnel are positively correlated with the coefficient of subgrade reaction and grouting volume,while negatively correlated with the yield stress of the strata.As the cover-to-depth ratio of the tunnel increases,the final uplift of the tunnel within the grouted range decreases,while the uplift efficiency exhibits negligible change.The proposed method provides support for the design of grouting for uplift of shield tunnel,in soft clayey ground.
作者
孟凡衍
贾琪
陈仁朋
陈曈
程红战
MENG Fanyan;JIA Qi;CHEN Renpeng;CHEN Tong;CHENG Hongzhan(College of Civil Engineering,Hunan University,Changsha 410082,China;Hunan Provincial Engineering Research Center of Advanced Technology and Intelligent Equipment for Underground Space Development,Changsha 410082,China;Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education,Changsha 410082,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2024年第11期2401-2409,共9页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(52378338,52108318,51938005)。
关键词
结构性黏土
注浆
隧道抬升
超孔压消散
固结沉降
structured clay
grouting
tunnel uplift
dissipation of excess pore water pressure
consolidation settlement
