关键词: 公路隧道, 自稳能力, 施工方法, 大跨度浅埋, 赤平投影

Abstract: The shallowly-buried long-span Hanjialing tunnel is an integral part of the expansion project of Shenyang-Dalian expressway in Northeast China. Based on the field survey of geological conditions, the geological characteristics of key positions of the tunnel were investigated, especially how the new Austrian tunneling method (NATM) construction process will affect its stability. Some measures are proposed to take so as to play fully the role of host rock in construction process. The practice showed that the geological/engineering conditions of the long-span tunnel are very complex, and it is of importance to monitor rocks structural plane and deformation and to readjust timely the construction schedule and relevant technologies. It is stressed that the self-stability mechanism of key positions should be monitored and controlled carefully so as to play fully the role of self-stability of hast rock. What the measures proposed to take and relevant experience will benefit the construction of the other similar projects.