地面出入式超浅埋盾构隧道静力响应模型试验

Experimental research on static response of ground penetrating ultra shallow-buried shield tunnel without working shaft

以地面出发超浅埋盾构隧道为研究背景,建立相似物理模型,研究地面出入式盾构隧道多工况的静力响应。基于相似比理论,控制分层土弹性模量与原型场地等效,并保证模型盾构隧道横断面刚度和纵向拼装刚度与原型等效,模拟原型超浅埋盾构隧道的受力状态。重点研究在静力作用和地面超载工况下模型的直径变形、接缝张开量和土压力响应,揭示在静力作用下地面出入式盾构隧道的静力响应特征,模拟隧道在运营工况下的结构响应。研究表明,随着埋深从-0.5D(隧道直径)增大至0.5D,隧道的直径变形由“竖鸭蛋”逐渐转变为“横鸭蛋”形式,在埋深为-0.1D时直径变形达到最大,纵缝张开量的总体趋势与直径变形呈现正相关性,结构水平向土压力可近似为三角形分布。

A similar physical model test was established to study the static response of the ground penetrating shield technology(GPST)tunnel with multiple working conditions.Based on similitude ratio theory,the mechanical state of the prototype tunnel was reproduced by controlling the layered soil modulus and prototype field equivalent and ensuring the cross-sectional and longitudinal stiffness of the shield tunnel after assembling.The diameter distortion,joint deformation,and earth pressure of the model under gravity and overload were tested,therefore,the static response characteristics of the GPST tunnel were investigated.The results showed that with the increase of burial depth from-0.5D to 0.5D,the tunnel diameter deformation gradually changed from"vertical egg"to"horizontal egg",and reached the maximum value when the burial depth was-0.1D.Besides,the overall trend of the longitudinal joint opening was positively correlated with the diameter deformation,and the horizontal earth pressure of the structure could be approximated to triangular distribution.