Abstract:
The project area is a high mountain valley topography that strongly influenced by geological tectonic movements with complex geological conditions。the original design is open-wire, According to the qualitative and quantitative analysis, it doesn't meet safety requirements when the geological conditions changed because of the heavy rain and excavation。in order to avoid its adverse effects, a small angle cross section tunnel structure is used in this project, which divide the large cross section into three segments: Wall area、reducing cross area and enlarging and excavation area, Each area has a special excavation and support design parameters, and this system has been deployed successfully, I hope that this paper will provide some experience and reference significance for similar projects in the future.