TENAX RIVEL system for reinforced soil walls and steep slopes

TENAX RIVEL

Integrated geogrid system/metal formwork/vegetative mat

The reinforcing element provided by the TENAX RIVEL System is composed of a TENAX TT series monoriented HDPE geogrid (1) and on the face by a non structural guiding and supporting "left in place" formwork (2), produced by bending to the slope angle a sheet of welded wire mesh (150 x 150 mm mesh or also 200x200 mm, Ø 8 mm).

The formwork is supplied with hooked tie rods that guarantee the geometric stability of the formwork itself during the soil compaction phase.

The use of the "left in place" formwork provides a rapid rate of installation and more accurate project construction and finished face.

A vegetative biomat (3) is placed on the inner face to protect the face against the erosion and create an adequate surface for the eventual hydro-seeding or sowing of suitable grasses.

Inert material for embankment
The reinforced soil technique allows, the use of almost any kind of fill soil; however, the use of granular material having a good drainage capacity and a high internal friction angle, is suggested. Better to avoid the use of very coarse gravel and big cobbles since the compaction of the soil would results much more difficult. In case the inert material available in situ presents poor geomechanical properties, the mixing with imported gravel and sand is sometimes suggested. Near the face the fill soil shall be a good topsoil so as to create the best conditions for grass growth. The fill soil shall be spread and compacted, in several lifts with a thickness of 0.30 m - 0.35 m, until reaching a minimum 95% Standard Proctor density.

TENAX TT mono-oriented geogrids - Reinforcing elements
The reinforcement element foreseen for the TENAX RIVEL System is a mono-oriented HDPE geogrid of the TENAX TT series. The TENAX TT geogrids have a chemically inert structure that, thanks to particular and patented technological processes, reaches very high tensile strength. The aperture of the geogrid allow the soil particles to interlock, thus providing an optimal lateral confinement to the granular soil, therefore limiting the related movements and increasing the shear resistance.

Welded wire mesh formwork
The TENAX RIVEL System on the face makes use of a sacrificial formwork made up of welded wire mesh mechanically bent to the desired slope angle (mesh 150 x 150 mm or 200 x 200 mm; Ø 8 mm). The horizontal and the inclined sides of such formworks are linked by special hooked steel bars that guarantee the geometrical stability of the formworks, even during the compaction of the soil. The use of such formwork allows fast installation rates, coupled to an accurate and uniform face finishing.

Biomat
A biomat is placed inside the wrapping of the reinforcing geogrid to protect the face from rain fall and wind erosion and to constitute a proper medium on which the hydroseeding of suitable herbaceous essences can be done.

Hydroseeding
The last phase of the work consists in hydroseeding the slope face during the most suitable climatic period. The integrated hydroseeding mix consists of herbaceous essences with long root apparatus together with conglomerating and colloidal materials, humus and fertilizers containing long lasting micro and macro elements.

The vegetated face may be obtained also by planting willows, rootstocks and bushes, placed in between the reinforced layers; in such a way a better root network is obtained which in turn provides an even more uniform and dense vegetation coverage.