Secudrän® 151WD 501, 3.80m x 35m
Bentofix® B 4000, 4.85 m x 30 m
Secudrän® drainage mat installed over Bentofix® 260000 sqm
The largest landfill in Estonia, Pääsküla Landfill, just outside the capital city of Tallinn, was capped in 2005 with the work finishing in 2006. Although parts of the landfill had been in place for many years, substantial settlements were expected. This was confirmed by on-site measurements during the capping operation. The original design was based on a soil-gas-drainage layer, a GCL, a gravel-rainwater drainage layer and a top layer of soil, thickness 1 m.
Because of the expected settlement a flexible but robust GCL was selected. For this project, we supplied Bentofix® B 4000 because this product has a nonwoven geotextile and a woven scrim reinforcement, thus the product can stretch past the breaking point of the woven reinforcement and still stop the bentonite from escaping.
All the products are needle-punched together so that there was no worry of any internal delamination.
The contractor had problems in sourcing the right quality of gravel for the rainwater drainage layer so it was decided that this drainage layer would be replaced by NAUE’s Secudrän® 151 WD 501. NAUE’s sister company, BBG, was able to show the supervising engineers that the Secudrän® could outperform the original specified gravel layer.
The main contractor for this capping project was Skanska’s Estonian company. The installation of the Bentofix® and Secudrän® was carried out by NAUE’s agent in Estonia, Via Con Eesti. The supervisors for this project were C + E from Chemnitz, Germany. Installation of Bentofix® on the prepared subgrade. Placement of cover soil over Bentofix®.