Engineering Geology

By the effect of exterior condition such as the terrain around, geology, environment, weather and inner stress, the construction of tunnel gate is a difficult problem all along. Its construction schedule also affects the whole tunnel construction’s speed and quality. So it’s very important to have reasonable technology means and inspecting and surveying measures to guide the construction. According to the engineering geology conditions of the portal section of the highway mountain tunnels, with the construction of the Dawan tunnel gate, this paper expounds the relevant measures and methods which can excavate into the portal section of the tunnel. Conducted with the principle of NATM and the feedback from the information of monitoring measures, the construction of the tunnel’s portal section has been going on safely and successfully.