隧道仰拱组合结构的现场试验研究

在复杂地质条件下长大隧道施工过程中,为了控制隧道围岩的过大变形及加快隧道施工进度,需要将仰拱及时封闭.通过对仰拱采用钢筋混凝土预制板和干硬性混凝土组成的组合结构的现场试验研究,把仰拱上的荷载通过预制板间接传递给铺底干硬性混凝土,并充分利用干硬性混凝土强度增长快、受力后变形较小的特点,使仰拱组合结构在隧道掘进的两次出砟间隙时间内达到能通行汽车的要求.对组合结构承受不同荷载时钢筋混凝土板顶面的沉降变形及钢筋混凝土预制板和铺底混凝土之间的接触压力进行现场量测,并用有限元计算方法对试验结果进行分析验证.结果表明,由本文设计的隧道仰拱组合结构,能够增强隧道的施工安全和加快施工进度.

Field Test Study on Composite Construction of Tunnel Invert

During the construction process of the long and large railway tunnel with complicated geological conditions, it is necessary to seal the invert in order to control the oversize deformation of the surrounding rock and construct the tunnel quickly. The field test is made about the tunnel invert that combined with precast rein- forced concrete slab and dry concrete. The load on the invert is indirectly transferred to the dry concrete of the grate layer, and it fully makes use of the characteristics of the dry concrete that its intensity increases quickly and the deformation is small when pressed, and thus, the trucks can go through the composite construction between the times of two ballast transfers. At last the top surface deposition of the precast reinforced concrete slab and contact pressure between the precast reinforced concrete slab and dry concrete with different loads are measured, and the finite element method is used to analyze and verify the conclusion. The result indicates that the tunnel invert of composite construction designed according to the article can improve the construction safety and speed up the construction.