THE PROBLEM
There was presence of 15 failed slopes along Highway A4. Slip failures in the cutting slopes required reparation whilst maintaining operation of the highway below.
THE SOLUTION
Reinstatement of soil slopes utilising TensarTech SlipRepair System. This cost effective solution required no import of fill materials, which resulted in financial and environmental benefits. The failed soil was reinstated, with the stability of the reconstructed slopes ensured by the incorporation of horizontal layers of Tensar geogrid reinforcement within the soil mass.
PROJECT DESCRIPTION
Prior to the installation of Tensar Technology, slip failures were identified along the motorway in several places and were growing with time. Following analysis of soil conditions and calculation of slope stability, TensarTech SlipRepair System was chosen as a quick and efficient repair method for soil slopes.
Re-construction of the failed slopes used 3 – 7 layers of Tensar uniaxial geogrids as primary reinforcement with Tensar biaxial geogrids as secondary reinforcement between the primary geogrids to maintain local slope stability at the face. Each 1m thick layer was filled with the failed soil and the geogrid wrapped up and around at the face to retain the fill. Each reconstructed section was covered by a thin layer of topsoil and sown with grass seed.
As a preventative measure, the same approach was used in sections between existing slip failures where the Client expected similar problems to develop with time if left untreated.
The length of cutting which required the slope repair was 250m. Slip failures occurred on both the south and north side of Highway A4. The total length of repaired slope was 520m.
