Dutch N201 Road Embankment with EPS Geofoam

Abstract

The new section of the provincial road N201 between the Amstel aqueduct (founded on piles) and a junction near Uithoorn characterizes a 200 m long lightweight road embankment which is necessary because of local settlement sensible subsoil. In total 14,000 m³ EPS is built-in in this up to 4.1 m high embankment despite applied preloading and partial weak subsoil replacement. In the scope of the designing process the subsoil parameters for the Plaxis models were adjusted on the basis of the monitoring results. In this way the road embankment design was optimized regarding both the structural and the settlement behaviour. However, visual inspections carried out by the supervision team of the province North Holland in combination with quality controls in laboratories during the construction process pointed out serious shortcomings of delivered materials and the construction work. Therefore the design had to be adjusted twice to guarantee the design life of the lightweight road structure and to minimize the settlements. Specialized technical assistance was necessary to ensure timely and effective checks needed and to prescribe appropriate compensatory measures. Obviously, contractors often underestimate the consequences of the use of EPS in engineering practice and the differences between geofoam blocks and other conventional embankment materials.