Autumn 2014

Improvement in road safety N331

The N331 between Zwartsluis and Vollenhove (NL) is currently being widened to improve road safety and achieve a better flow of traffic. TenCate Geolon® PP 80 was used in order to strengthen the weak soil. This represents a saving in materiel costs, construction time and CO2 footprint.

The N331 main road connects the A28 near Zwolle with the A6 near Emmeloord. The province of Overijssel is engaged in fundamentally improving road safety on the Zwartsluis-Vollenhove route. Until recently this was an accident blackspot.

3 geosynthetics N331 P1050161

The work was not without setbacks. After the removal of the asphalt surface and the foundations the contractor attempted to install a new road structure on waterlogged cunette soil. A cunette is a channel that occurs as a result of dredging during the construction of a deepened road or railway in an area of weak soil and a high groundwater level. Due to the weakness of the cunette soil it was not possible for the heavy road construction materiel to bring in and incorporate infill sand for the new road embankment. An embankment of sufficient density and load-bearing capacity could not be built. The soil that was brought in displaced the waterlogged material in the cunette, allowing these to mix.

3 geosynthetics N331 4240

In order to reinforce the cunette soil sufficiently, thus enabling it to bear heavy loads, TenCate Geosynthetics advised the use of TenCate Geolon® PP 80. This made it possible also to prevent the saturated subsoil from mixing with the embankment material. In total 126 rolls of TenCate Geolon® were supplied: an area of 80,000 m2. After this geotextile was installed the cunette could be filled in and compacted.

The use of TenCate Geolon® produced savings in both materiel costs and construction time, thus also in inconvenience to traffic and to local residents. Construction vehicles soon ensured the further construction of the road structure. It was also possible to prevent the cunette soil having to be dug out right down to the solid substrate, material having to be removed and new material supplied and incorporated. All in all this constituted a significant reduction in the use of natural raw materials and in CO2 emissions.

Blue fabric (Tecawork Blue 65287)