Essentials of the construction and exploitation of hydraulic tunnels in karst of eastern Herzegovina

Abstract

The main problem in the process of construction, and it also proved in practice during exploitation of hydrotechnical tunnels constructed in the karst of eastern Herzegovina, are caverns. Of all the problems that may occur in the process of construction and during exploitation of hydrotechnical tunnels constructed in the Upper Cretaceous limestone rocks, only caverns have the characteristics (size, shape, type of backfill, water inflow) which, in extreme cases, represent a problem that is difficult to solve. In such circumstances, the tunnel construction is subject to unpredictable and sometimes devastating impairments. Cavern is a term that represents a wider area within the karst sediments, which can be partially backfilled with debris, sometimes completely empty, connected with the ground surface by karst channels. Accumulation tunnels for power plants, i.e. the tunnels where the water flow is under pressure, are particularly susceptible to these impairments. This study introduces practical problems that have occurred in hydrotechnical tunnels constructed in the hydropower system of Trebišnjica.

Keywords

• hydrotechnical tunnels
• karst
• cavern
• rebuilding