Keller installed around 11550 pcs of Ø600 mm and Ø800 mm Lime Cement Columns as ground stabilization for the new arena and extension building for Os Skole using 2 rigs for a total of 175.000m. The Lime Cement columns were installed to bedrock (27m max depth) in an area with very sensitive clay (quick clay).
The project
On behalf of the Halden Kommune, AF Gruppen Norge AS has been the main contractor of all works regarding the new Arena and extension of the existing school and hired Keller as a subcontractor for the ground stabilization works in order to treat the sensitive clay in the area and reach the design excavation level.
The challenge
- Tight time schedule, utilization of 2 rigs in tight areas
- Coordination with other subcontractors for continuation of excavation and concreting works
- Delivering of Binder material ( Kalk/cement and Multi/cement) more than 4.200 tons in total
The solution
The solution to the project following the design from Multiconsult was to use 2 rigs with the maximum drilling depth available in the fleet of Keller with state-of-the-art GPS and IT infrastructure in order to comply with the high-quality standards of the Project. Additionally, 58 FKPS testing points were selected and tested in order to verify the expected strength of both binder material in these challenging soil conditions. Also, a connection to the existing sheetpiles, critical for global stability, was achieved using the Ø600 mixing tool.