The Reinforced earth is one of the solutions that can be used for retaining earth. The picture shows an example from Egnatia Odos, Greece. At the top of the retaining wall is founded the opposite direction of the traffic on the highway.
As suggested by David H. Barker, Nottingham Trent University, this hexagonal shape of facing panel has been used by the West Yorkshire/Jones System in the 1980's - but it must have been adopted by others by now.
- The Mechanically reinforced earth is also called a "gravity" wall and its design is based on the reinforcement of the earth through metal or plastic intrusions, which provide a "pseudo-cohesion" allowing the earth to stand vertical. Also friction stresses develop based on the angle of friction (delta) between soil and reinforcement or a combination of friction and passive resistance with geo- and wire grids. Different design systems have different contributions from each resisting stress.
- Types of reinforcing are: Metal strips and rods, geotextile strips and sheets and grids, or wire grids. These materials are fastened to the facing unit and extended into the backfill some distance. (See Fig. 2, Bowles 1997)
- In Fig. 1 and 3 you can see the facing units used in Egnatia Odos. The metal rods which were used in that project were fastened to those rectangular units which are shown in the pictures. The purpose of the facing units, is to maintain appearance and also to avoid soil erosion at the face of the earth block between the reinforcements. It is assumed in Vidal's Reinforced Earth theory that there is no load imposed by retained fill on the rear of facing units.
Joseph, E. Bowles, Foundation Analysis and Design, McGraw-Hill, 1997 edition.
Texts by: Dimitris P. Zekkos & David H. Barker, Faculty of Construction, Computing & Technology, Nottingham Trent University
Photos by: Dimitris P. Zekkos.
Figure 1: View of the reinforced earth. On the top of the wall is also a road.