回水河4号连拱隧道南洞口段处于软土层内,地形西高东低隧道存在偏压,在雨季顺坡向的土岩分界面渗水积水极易诱发边坡失稳。在试验分析的基础上,采用旋喷桩加固软基、混凝土灌注桩稳定边坡、大直径钢管为拱架锁脚、土岩分界面高压水泥浆注浆等工程措施,有效地保证了隧道的施工安全与长期稳定。 The South Dongkou Section of the No. 4 Arch Tunnel in the Shuikuihe River is in a soft soil layer. There is a bias in the tunnel of the west high and the east low in the terrain. Water seepage in the rock - soil interface along the slope in the rainy season can easily induce slope instability. On the basis of the experimental analysis, the engineering measures such as rotating grouting pile to reinforce soft foundation, concrete pouring pile to stabilize the slope, large-diameter steel pipe to lock the foot of the arch and high pressure grout grouting at the earth and rock interface are adopted to effectively ensure the tunnel’s Construction safety and long-term stability.