砂土液化对越江盾构隧道上浮行为的影响研究

Influence of Sand Liquefaction on Uplift of River-crossing Shield Tunnel

越江盾构隧道修建时,部分隧道不可避免地穿越了可液化地层,需要对砂土液化下盾构隧道的上浮行为进行研究。文中以某穿越液化土层的越江通道为工程背景,通过数值模拟建立等效衬砌模型和接头衬砌模型,采用单变量分析法研究衬砌外径、衬砌厚度和衬砌接头对隧道上浮力学特性的影响规律。结果表明,衬砌厚度越小,衬砌的上浮位移和轴向应力越大;衬砌外径越大,衬砌的上浮位移越小,但是轴向应力反而越大;液化土与非液化土的交界处存在应力集中现象,实际工程中需要对交界处的衬砌接头部位进行加固。

During the construction of river crossing shield tunnel,some tunnels inevitably pass through liquefiable stratum.It is necessary to study the floating behavior of shield tunnels under sand liquefaction.Based on the engineering background of a crossing-river passage crossing the liquefied soil layer,the equivalent lining model and joint lining model are established through numerical simulation,and the univariate analysis method is used to study the influence of lining outer diameter,lining thickness and lining joint on the floating mechanical properties of the tunnel.The results show that the smaller the thickness of the lining,the greater the floating displacement and axial stress of the lining;the larger the outer diameter of the lining,the smaller the floating displacement of the lining,but the greater the axial stress;there is a stress concentration phenomenon on the boundary between liquefied soil and non-liquefied soil,so it is necessary to reinforcement the lining joints at the junction in actual project.