双孔盾构隧道近接施工离心模型试验研究

Study of adjacent construction of two tube shield tunnels by centrifugal model test

通过室内离心模型试验模拟双孔盾构隧道近接施工,研究了衬砌结构横向内力的量值、分布规律以及随盾构推进距离和两隧道相对位置的变化规律。结果表明,衬砌结构拱顶和拱底内侧受拉,左右拱腰外侧受拉,拱底出现最大弯矩;整个结构均受压,拱顶和拱底处轴力较小,左右拱腰轴力较大;既有隧道施工完成后,结构内力基本呈对称分布,且随着新建隧道的施工,两隧道结构内力将随其相对位置的变化而变化;新建隧道施工对既有隧道结构内力影响明显,设计施工时应采取相应的加强措施。

The adjacent construction of two tube shield tunnels was simulated by centrifugal model test method.The value and the distribution regularities of structural transversal internal forces and their variation with advanced distance of shield machine and the relative positions of two tunnels were studied.The results showed that the inside of top and bottom of lining structure subjected to tension,while the outside of left and right hance subjected to tension;and the largest bending moment occurred on the arch bottom. The whole structure was compressed;and the smaller axial force occurred on the arch crown and arch bottom,while the bigger occurred on the left and right hance.The distribution of structural internal force was symmetrical after the construction of the first tunnel;and the structural internal force of two tunnels changed with their relative position when the second tunnel was constructed. The new tunnel construction had obvious influence on the structural internal force of the existed tunnel;and the corresponding strengthening measures should be taken in the design and construction.