Forggensee is a lake in Bavaria and the largest water reservoir in Germany, created by the Rosshaupten Dam, built in the 1950s. BAUER Spezialtiefbau GmbH was awarded the contract for construction of the 70 m deep cut-off wall but also to implement soil stabilization. Percussion drilling and tube-amanchette injections were executed to a total scope of 1,100 m. The data monitored during the drilling works also provided valuable information for the subsequent grab and cutter excavation operations for the cut-off wall trenching. The data were digitalized and a 3D model was produced step by step, thereby documenting the real time monitored data and help compile a visual model using Bauer's data management system b-project. A unique application was the installation of a BAUER Mixed-In-Place (MIP) structural retaining wall aligned either side of the subsequent cut-off wall trench. The MIP was designed as a barrier against the potential risk of high water loss rates during the excavation process, which was highlighted as a residual risk by the Technical Expert Panel.
Karsten Beckhaus, Dirk Beier and Michael Baltruschat
Keywords:
dam rehabilitation, soil stabilization, Mixed-In-Place, MIP, cut-off wall
Publisher: DFI and PFSF