How to install a geogrid - laying technology

Purpose of geogrid

Geogrid - geotextile polymer material designed to reinforce earthen surfaces. It is a structure of textured polymer strips interconnected by thermal or ultrasonic welding. They form cells arranged in a checkerboard pattern.

When stretched in the working plane, the grating forms a deformation-resistant frame that can reliably fix soil, sand, concrete or other filler.

The use of grid enables to:

• simplify work with weak soil;

• speed up construction time;

• eliminate the risk of uneven subsidence and frost heaving of the soil;

• extend the service life of pavement;

• increase the intervals between repairs;

• reduce operating costs.

The application scope of geogrid is quite wide. It is used for:

• pavement reinforcing;

• construction of anti-erosion strips;

• prevention of erosion of reservoirs and coastal zones;

• reinforcing the supports of the bearing walls of buildings and structures;

• arrangement of parking lots, heliports and sports grounds and airport runways;

• reinforcing the landscape in areas with slopes;

• implementation of works on gardening of the site;

• creation of terraces and garden plots.

Preliminary work before laying

As mentioned above, the installation of a geogrid is not a complicated process, but it is necessary to follow a certain technology during installation in order to avoid premature destruction of the structure.

The most important point is the preparation of the site, the soil surface of which must be carefully leveled before the grid is rolled onto it. All stones and boulders larger than 12 cm should be removed and all holes filled up. At the same time, it is necessary to correctly divide the territory into separate intervals and plan the entire surface of the slope. Otherwise, the geogrid may be damaged.

When carrying out work on embankment slopes, it is necessary to compact the top layer with a hand roller or fiberboard plates.

Before laying the geogrid on unstable soil , a set of preparatory work is carried out aimed at preserving the vegetation layer. All vegetation is cut to soil level so that only the root system remains. If crushed stone, compacted sand and gravel are present in the soil at the construction site, this gives good geotechnical characteristics and in this case it is possible to do without backfilling an additional layer and lay the geogrid directly on the surface.

When reinforcing different types of structures, the volume and specifics of the preparatory work may vary.

For example, before installing a grid to protect pipelines, soil is poured under it, which must be compacted, and then an L-shaped synthetic material is laid on top, which is fixed with a construction stapler or anchor cord. Also, to increase the strength of the structure, you can lay an additional layer of geotextile, which is attached to the grid using fusion.

To reinforce the slopes, according to the previously studied characteristics of the site, drawings are being prepared, on the basis of which it is necessary to build a sole for the slope, compact the soil and then lay the geosynthetic grid.

Before reinforcing the supporting structures , the surface of the site is also leveled and compacted, but in addition, drainage is prepared and profiles are installed, and then the geogrid is stretched.

Geogrid installation

After the preparation of the site is complete, you can start laying the grating.

It is necessary to carry out laying of the geogrid completely stretching over the surface of the soil, having previously fixed its edge with the help of anchors. This is necessary to provide the material with the necessary stretching and the acquisition of a rectangular shape for each cell.

This requires each interval to be checked for full stretch and the edges of all adjacent intervals to be carefully aligned and joined together. After that, additional anchors are installed, their number should be at least 3 - 4 pieces per square meter.

If the slope is too deep and the first module does not reach the base of the slope, a second interval of material may be required.

Filling the grid cells

When the grid is fixed, you can start filling the cells.

The material most often used for filling is crushed stone, soil or concrete of grade not lower than M200. Filling is carried out both manually and with the help of specialized equipment.

Importantly, the layer of backfill material should be 50 millimeters higher than the walls of the grid.

After filling all the cells, the main anchors that perform the supporting function remain in place, and the remaining anchors can be removed.

Bearing anchors have a similar design as mounting anchors, but serve to fix the grid on the soil surface. They are placed evenly over the entire area of the grid at a distance of 1 - 2 meters from each other.

When the installation of the grating is carried out on slopes, wooden pegs are used instead of load-bearing anchors, and soil or crushed stone is used as a filling material.

Often the cells of the grids are filled with vegetable soil, after which it is compacted and grass seeds are sown for the lawn. Each roll of such a lawn must be attached to the slope with pegs measuring 25 x 25 x 250 millimeters, on average six pieces are required per roll. To achieve the fastest possible germination of seeds, they must be mixed before sowing with crumbly homogeneous black soil. It will take about 40 grams of seeds per square meter.

Conclusions

The geogrid is used to reinforce earthen surfaces and makes it possible to protect road structures, runways and supports of the walls of structures from premature destruction, coastal zones from erosion and reinforce the landscape of a personal plot.

The process of laying a geogrid is quite simple, but certain instructions must be followed during its installation. First of all, it is required to prepare the area to be repaired, clear of stones and cobblestones, level the pits, if necessary, remove vegetation and compact the top layer.

After fixing the grid, all cells should be filled with soil, crushed stone or concrete. In some cases, the cells are filled with vegetable soil, after which grass is sown for the lawn.