地下水位变化对盾构隧道的影响研究

Study on Influence of Water Level Fluctuation on Shield-bored Tunnel

为研究地下水位变化对盾构隧道结构的影响,利用有限元理论,建立了地下水位变化时盾构隧道结构的有限元模型,该模型可预测出不同地下水位时盾构隧道及地面变形情况,揭示出不同水位时的盾构隧道在土中的位移变化规律。结果表明:地下水位发生变化会对盾构隧道产生一定的影响。地下水位上升会导致地表浅层土体发生回弹变形,并且下方有盾构隧道的地表的回弹值要比下方没有盾构隧道的地表的回弹值小;当地下水位从盾构隧道拱底处逐渐升高到中心处和拱顶处时,盾构隧道结构会出现竖向位移和边壁的侧向位移,并且水位越高,隧道的竖向位移和边壁的侧向位移越大。

A finite element model of shield-bored tunnel structure is established, so as to study the influence of water level fluctuation on shield-bored tunnel. The deformation of the tunnel and the ground under different water levels can be predicted and the displacement rules of the shield-bored tunnel under different water levels can be revealed by means of the model. The study results show that ： 1 ） Rebound deformation will occur to the shallow soil layers at the ground sur- face when the water level rises. The rebound value of ground under which shield-bored tunnel exists is smaller than that of ground under which no shield-bored tunnel exists. 2） Vertical displacement of the tunnel structure and lateral dis- placement of the sidewall will happen when the ground water level rises from the invert to the crown. The higher the ground water level, the bigger the displacement value.