摘要
在软土地层中应用盾构地中对接法能大大缩短长隧道施工周期,但先、后行盾构施工在盾构对接段产生的超静孔隙水压力会影响土体应力状态和地层稳定性。建立软土地层盾构地中对接法的流固耦合模型,在时间方面,分析了盾构地中对接横断面上不同距离的超静孔隙水压力时间分布;在空间方面,分析了先、后行盾构施工引起的超静孔隙水压力纵向分布,以及盾构对接施工过程引起的超静孔隙水压力横断面分布。另外,分析了盾构地中对接施工对孔隙水压力的扰动规律,并进行施工参数分析。结果表明:完成盾构对接时,盾构施工对拱顶扰动范围最大,侧边次之,底部最小;后行盾构施工对开挖面前方的超静孔隙水压力影响范围是先行盾构施工的1.5倍,其值大约为3.4倍的隧道直径;当分层土体的渗透性差异过大时,会出现超静孔隙水压力突变的情况;在盾构地中对接施工过程中,先行盾构施工阶段产生的扰动影响要远大于后行盾构,至对接位置时,先行盾构对拱顶产生的孔压扰动指标是后行盾构的2倍左右;对接点处未进行注浆加固时,建议先、后行盾构在距对接点2D(D为隧道外径)前,将掌子面支护力减小至0.8倍标准掌子面支护力,或在先行盾构到达对接点前进行超前注浆加固,以减小盾构对接施工过程的扰动影响。
The application of shield docking method in soft clay can greatly shorten the construction period of long tunnels,but the excess pore water pressure generated by the first and second shield construction in the shield docking section can affect the soil stress state and formation stability.The fluid-structure coupling model for the shield docking method is established in soft clay.In terms of time,the time distribution of excess pore water pressure at different distances on the shield docking cross-section is analyzed.In terms of space,the longitudinal distribution of excess pore water pressure and the cross-sectional distribution of excess pore water pressure caused by the first and second shield construction are analyzed.In addition,the disturbance law of pore water pressure caused by shield docking construction is analyzed,and the construction parameters are analyzed.The analysis results show that when the shield docking is completed,the disturbance range of shield construction on the top of the arch is the largest,followed by the sides,and the bottom is the smallest.The influence range of excess pore water pressure generated by shield construction in front of the excavation face is 1.5 times that generated by the first shield construction,and its value is approximately 3.4 times the tunnel diameter.When the permeability difference of layered soil is too large,a sudden change in excess pore water pressure will occur.During the shield docking process,the disturbance caused by the first shield construction stage is significantly greater than that caused by the second shield,and the pore pressure disturbance index of the first shield to the arch is about twice that of the second shield at the docking position.When no grouting reinforcement is carried out at the docking position,it is recommended to reduce the supporting force of the tunnel face to 0.8 times the standard supporting force 2D(D represents the outer diameter of the tunnel)away from the docking position for both the first and second shields,or to perfo
作者
王彪
陈星欣
尹清锋
郭力群
何明高
WANG Biao;CHEN Xing-xin;YIN Qing-feng;GUO Li-qun;HE Ming-gao(School of Civil Engineering,Huaqiao University,Xiamen,Fujian 361021,China;China construction Communications Construction Group Co.Ltd.,Beijing 100142,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第S01期535-549,共15页
Rock and Soil Mechanics
关键词
软土地层
盾构对接
超静孔隙水压力
扰动度
soft clay
shield docking
excess pore water pressure
disturbance degree
