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密切跟踪浏阳河隧道的仰拱施工状态,开展现场测试,基于大量的实测数据研究水下浅埋公路隧道施作仰拱产生的力学效应。研究结果表明:仰拱开挖使上拱部不同部位的围岩与初衬接触压力发生不同的变化,有的部位接触压力增大,而有的部位接触压力却减小;整个初衬层闭合能制约上拱部初衬拱顶沉降和水平收敛的发展;挖掉仰拱初衬上的临时填土会使型钢拱架在仰拱底的应力有较大增加;仰拱混凝土浇注完后,仰拱初衬背后的水压力呈增加之势;仰拱混凝土既分担了部分围岩荷载,又起到了安全储备的作用;仰拱混凝土终端与仰拱开挖面的距离取为25~35 m是合理的。
Closely tracking the inverted arch construction status of Liuyanghe Tunnel and carrying out on-site testing, the mechanical effects of inverted arch under-water shallow tunnels are studied based on a large amount of measured data. The results show that the contact pressures of surrounding rock and primary lining of different parts of the arch vary with the excavation of inverted arch, and the contact pressure increases in some parts, but decreases in some parts; the entire primary lining closes Which can restrict the development of the initial lining of the arch and the horizontal convergence of the arch; excavating the temporary filling on the initial lining of the inverted arch will cause the stress of the arch steel arch at the bottom of the inverted arch to increase greatly; after the inverted arch concrete is poured, The water pressure behind the inverted arch lining is increasing. The inverted arch concrete not only shares part of the surrounding rock load, but also plays the role of safety reserve. The distance between the inverted arch concrete terminal and the excavation face of the inverted arch is 25 ~ 35 m Is reasonable.