Melo dam drilled steel pile wall: Restraining seepage through earth dam

Abstract

The Melo dam hydroelectric power plant in Nokia, Finland, was built between 1968 and 1971. The dam structure consists of a turbine hall on the right bank of the Kokemäenjoki river and a 120 m long earth dam adjacent to it. The earth dam was constructed with layers of moraine, gravel and rock fill. Over the years, seepage issues emerged, including a sinkhole in 2005, leading to temporary repairs. However, in 2019, a comprehensive renovation plan was initiated to develop a permanent solution. In 2022, KFS Finland carried out construction work to restrain seepage and ensure dam stability. This involved building a drilled steel pile wall along the entire length of the dam, using RD500 steel pipes drilled into the bedrock, reaching a depth of 67 m from the surface. The completed structure is now the deepest drilled pile wall in Finland, ensuring the dam's structural integrity for decades to come.