Abstract:

In this paper, a case study of Tsengwen reservoir transbasin diversion tunnel is presented, with the emphasis being placed on the topics of hydrology. Threedimensional hydrological model is applied to assess the amount of tunnel inflow and to estimate the effects on the adjacent groundwater environment. The hydrological model is established based on the regional geological maps and a series of geological investigations and insitu tests. The hydrological parameters are calibrated according to the results of the aquifer tests, the measurements of the observation wells and weirs within the tunnel and the total inflow at tunnel portals. The hydrological model can be used to assess the future hazards due to the tunnel inflow. The results of assessment provide a good feedback for tunneling design and construction.

Key words: water inflow in tunnel, hydrological model, back analysis