湘江大道浏阳河隧道是我国第一座用矿山法施工的水下浅埋小间距公路隧道,隧道采用台阶法开挖,初期支护大量采用全环布设的型钢拱架。隧道支护拱架的受力性状是支护体系稳定的关键控制因素之一。通过对施工现场钢拱架的应力和位移的测试,基于大量的实测数据,对拱架的受力性状开展研究。结果表明:型钢拱架在拱顶和仰拱底的应力较大;下台阶开挖、浇筑仰拱混凝土、拱墙二次衬砌均会使拱架的应力大小发生调整,后行洞爆破开挖使邻近的先行洞拱架局部应力增大;拱架的应力变化具有时空效应,且与河水的渗透有关。对型钢拱架的应力和位移测试结果验证了开挖台阶长度的合理性。 Liuyang River Tunnel in Xiangjiang River Road is the first shallow shallow buried small-pitch highway tunnel in China constructed by the method of mining. The tunnel is stepped excavation, and a large amount of section steel arch frame is used for initial support. The mechanical behavior of tunnel support arch is one of the key control factors for the stability of the support system. Through the test of the stress and displacement of the steel arch frame at the construction site, the mechanical behavior of the arch frame is studied based on a large amount of measured data. The results show that the stress of the arch steel arch in the arch and the bottom of the inverted arch is larger. The excavation of the next step, the pouring of inverted arch concrete and the secondary lining of the arch wall will make the adjustment of the stress of the arch, So as to increase the local stress of the adjacent advance cave arch; the stress change of the arch has the space-time effect and is related to the infiltration of river water. The test results of the stress and displacement of the steel arch frame verify the rationality of the excavation step length.