SIGNIFICANT ENGINEERING DEVELOPMENT An MSE approach embankment eliminates the need for retaining walls in conditions of limited space
The worldwide acceptance and use of mechanically stabilised earth (MSE) technology is one of the most significant civil engineering developments of the past 50 years, says retaining wall company Reinforced Earth.
MSE is the generic name for a composite material, comprising a frictional backfill, reinforcements and generally an external cladding.
The mechanical reinforcement of earth produces a material, which remains flexible, compared with earth that is chemically stabilised producing a rigid structure.
MSE finds application wherever heavy earthmoving is involved, including the development of roads, railways, bridges, dams, reservoirs, mines, airports and ports.
“Earth embankments are no longer limited to battered side slopes. “If frictional backfill is used and reinforce-ments are placed correctly in the fill then the external faces may be vertical, sloped or tiered. “Such embankments would be clad with elements, which are designed to accept local earth loads and protect the embankment from external forces, while not hindering the flexibility of the embankment.
“An MSE approach embankment eliminates the need for retaining walls in conditions of limited space. “This is of particular advantage if the foundations are poor and rigid retaining walls require special foundation improvement. MSE approach embankments accept dynamic loads particularly well and are of great benefit in earthquake prone areas,” says Reinforced Earth.
The company adds that the speed of construction is an added advantage, as the placement and compaction of the backfill should not be influenced in any significant way by the placing of the reinforcements and the cladding.
Other than approach embankments, the principal applications for MSE include the construction of massive earth gravity structures mainly for bridge abutments, retaining walls, headwalls to crushing plants, live coal storage bunkers, protective walls, and the raising of earth dams.
The material has also been, or is being, developed for use in the construction of reservoirs, rafts, reclaim tunnels, tailings dams and waste storage facilities.
“Design engineers working together with MSE service providers are constantly finding and innovating new applications for the material,” Reinforced Earth notes.
Reinforced Earth director Andrew Smith notes that the use of MSE in Africa is growing.
“For instance, Portuguese contractor Mota Engil will, later this year, construct 20 MSE bridge abutments and two MSE retaining walls as part of its Kampala Northern Bypass Expansion project, in Uganda,” he points out.