强震作用穿越不同位置粉土地层盾构隧道液化特性研究

Research on Liquefaction Characteristics of Shield Tunnel Passing through Silt Layers in Different Positions under Strong Earthquakes

强震作用下盾构隧道穿越饱和粉土地层的动力响应特性受到众多学者关注,饱和粉土层与盾构隧道位置关系的不同,隧道结构产生的动力响应特性不同。依托天津地铁5号线工程,采用动力时程分析法,对隧道结构位于粉土层下方、上方以及穿越粉土层时隧道结构的动力响应特性开展研究。结果表明:在强震作用下,粉土层液化程度随埋深增大而减少,受与隧道结构位置关系的影响不明显;粉土层在隧道结构上方时的结构位移大于粉土层在下方时,且与隧道结构距离越近产生的影响越大,当隧道结构仅上半部分位于粉土层时,隧道结构产生的位移最大为27.4 mm。

the dynamic response characteristics of shield tunnels passing through saturated silt soil under the action of strong earthquakes have attracted the attention of many scholars.The different positional relationship between the saturated silt soil layer and the shield tunnel affects the dynamic response characteristics of the tunnel structure.Relying on the Tianjin Metro Line 5 project,the dynamic time history analysis method is used to study the dynamic response characteristics of the tunnel structure where it is located below and above the silt layer and passes through the silt layer.The results show that under the action of strong earthquakes,the degree of liquefaction of the silt layer decreases with the increase of the buried depth,and is not significantly affected by the positional relationship with the tunnel structure;the structural displacement of the silt layer above the tunnel structure is greater than that of the silt layer below the tunnel structure;the closer the distance to the tunnel structure,the greater the impact.The maximum displacement of the tunnel structure is 27.4 mm where only the upper half of the tunnel structure is located in the silt soil layer.