Dutch A76 Highway Widening Using EPS Embankment with a Vertical Side

This article concerns the A76 highway widening (near the Kerensheide junction) using a lightweight fill with a vertical embankment. The A76 highway section (widened from 2 × 2 to 2 × 4 lanes) lies 4 m above a truncated slope and is situated between two concrete structures. The design of the fill should not decrease the stability of the current slope (with a high retaining wall at the toe of the slope) and had simultaneously to create sufficient space for the planned highway widening. In addition, the fill should have no influence on a crossing high-pressure gas pipe. The daily traffic load amounts to about 8600 trucks. These complex conditions have led to an extension of the highway cross section realized with EPS blocks with a vertical embankment; a first in the Dutch engineering practice. The EPS geofoam blocks were piled up 4 m above ground level and 2 m bellow the slope line. The performed parameter study confirmed that the friction between the EPS-blocks in combination with a low Poison’s ratio is sufficient to provide stability. No side support is needed to secure the slope stability after the completion of the highway A76 widening. Although the applied design method requires specific expertise, this design offers multiple advantages such as saving both space and costs, stability increase and a very short construction time.