Abstract: Xianglushan deep-buried long tunnel is a control project for the total construction period of the water diversion project in central Yunnan Province. With a total length of 62.596 km and maximum buried depth of 1 450 m, the tunnel is featured with large survey scope, complex geotectonic background and complicated karst hydrogeological conditions as well as sensitive groundwater environment. In survey period, the tunnel line was selected and its engineering geological and hydrogeological conditions and major engineering geological problems were basically ascertained. In this paper, we probe into such problems including the seismic resistance in high earthquake-intensity area and shear resistance of structures passing through active fractures, the environmental impacts of water inrush and mud intrusion, the high geostress, hard rock burst, large deformation of soft rock, high external water pressure, and the special geotechnical engineering problems of coal stratum and expansive soils. The research result offers a technical support for the design and construction of tunnel and a reference for researches on similar deep-buried long tunnels.

Key words: deep-buried long tunnel, water inrush from tunnel, hard rock burst, large deformation of soft rock, special rock and soil, water diversion project in central Yunnan