Rockfill and soil-rock mixtures in road embankments - a case study

Abstract

The development of transportation infrastructures has led to the need of huge earthmoving volumes, resulting in high embank- ments. In the construction of these embankments, rockfill and soil-rock mixture materials have been used. A 25 km roadway sec- tion, in the North of Portugal, with the difficult topographic conditions, has required the construction of large embankments. The involved formations are essentially granite (South area) and schist and greywacke (North area). To optimize the construction procedure and to evaluate their performance, physical and mechanical characterization of the materials was carried out and mon- itoring equipments were installed in some embankments. For that purpose, five embankments were selected, taking into account, essentially, the geometry and type of material used in their construction. Plate load tests were also performed, aiming at the eval- uation of the deformation modulus of the embankments. In order to measure displacements, vertical and horizontal inclinome- ters, extensometers and pressure cells systems were installed during construction. After construction, topographic marks on the embankment surface were installed. In this paper, the results of the mechanical characterization carried out in situ and in the la- boratory (large triaxial and oedometer tests) are presented. The installed monitoring equipments are also described. The dis- placements during the construction and deformations in service are herein presented.