Analysis on Application Effect of Prestressed Anchor Cable in Large Span Tunnel

Safety is the top priority during the construction process, the construction risk increases sharply with the increase of section size. Bifurcated tunnel structure is adopted in the entrance portal section of Bibanpo tunnel. The span of transition section reaches 25.79m (type A) and 22.11mm (type B), To ensure safety, a new support method of pre-stressed anchor was used. during the construction, we monitored the structure stress of primary support, and the tension stress of pre-stressed anchor cable, and we get that: the pre-stressed anchor cable on hence can support quickly, prevent plastic zone from deepening, decrease the load of primary support structure, especially the load of shaped steel. Through engineering practice, it can be concluded that pre-stressed anchor is an effective active support method. The successful application experience in Bibanpo tunnel is of great significance for similar projects.