AND EQUIPMENT SET FOR SUCH PROTECTION

Technical Field

The subject of the invention a method of protecting a soil from erosion, in particular, from the erosion caused by rainwater and wind, as well as an equipment set to implement such soil protection

Background Art

There are well-known methods of protecting a sloping ground surface through grass sowing or covering the land with the ready-made turf. There are also methods of protecting such surfaces by placing concrete hollow core slabs on the slope and filling the holes with humus mixed with grass seeds. Moreover, there are known methods of protecting soil with the use of humus mixed with grass seeds and geotextile. Such solutions were disclosed, for example, in the Polish patent application P-358972 and in the Polish patent PL188728.

Disclosure of Invention

The purpose of the invention was to achieve an effective, cheap and easy to implement method of protecting the soil from erosion.

A method according to the invention relies on that on the surface to be protected is placed a geotextile of a basis weight of 200 to 500 g/m ² and containing plant seeds in its structure. Then this geotextile is covered by a spatial geogrid with spatial cells of the sizes ranging from 200 to 500 cm ² and with a height of side walls ranging from 20 to 50 mm. Next the spatial geogrid is fixed to the ground by anchors and filled with humus.

In the method according to the invention a biodegradable geotextile or a geosyn- thetic geotextile can be used as the geotextile. In variant of the method according to the invention percentage of seeds in the geotextile ranges from 10% to 20% of weight.

In another variant of the method according to the invention is used a spatial geogrid which is made of a set of plastic strips of thickness ranging from 1 to 7 mm. In the set each of the stripes is permanently connected to the adjacent strip at regular distances, advantageously every 340 mm.

In next variant of the method according to the invention the plastic strips forming the geogrid are perforated.

fn another variant of the method according to the invention for every two square meters of the spatial geogrid from 2 to 3 anchors are used.

In yet another variant of the method according to the invention the anchors have a form of a rod bent at an angle of 180 degrees, advantageously of a rod of a diameter of 8 mm.

An equipment set for protection a soil from erosion consists of a geotextile of a basis weight of 200 to 500 g/m ² and containing plant seeds in its structure. The set consists also of a spatial geogrid with spatial cells of sizes ranging from 200 to 500 cm ² and with a height of side walls ranging from 20 to 50 mm, as well as of anchors. The geotextile of the equipment set according to the invention may be a biodegradable geotextile or a geosynthetic geotextile.

In one variant of the equipement set according to the invention the percentage of seeds in the geotextile ranges from 10% to 20% of weight.

In another variant of the equipement set according to the invention the spatial geogrid consists of a set of plastic strips of thickness ranging from 1 mm to 7 mm. Moreover, each of the strips is permanently connected to the adjacent strip at regular distances, advantageously every 340 mm.

In another variant of the equipment set according to the invention the plastic strips forming the geogrid are perforated.

In another variant of the equipment set according to the invention it contains from 2 to 3 anchors for every two square meters of a soil to be protected.

In yet another variant of the equipment set according to the invention the anchors have a form of a rod bent at an angle of 180 degrees, advantageously of a rod of a diameter of 8 mm. The solution according to the invention enables rapid, effective and low-cost protection from erosion of all types of land surfaces such as embankments, ditches and flood embankments. Additional advantages of the solution are: possibility of conducting ground works even before and after the growing season, getting almost 100% of biologically active ("green") surface, a large capacity to keep the seeds in the moisture which guarantees intense vegetation practically independent from the degree of the land slope.

Brief Description of Drawings

The invention is presented schematically in figures of the drawing. Fig. 1 shows a vertical section of the slope protected using the method accorodfng to the invention. Fig.2 shows a perspective view of an exemplary spatial geogrid used in the process of realisation of the invention. Fig. 3 depicts the top view of the anchored geogrid prepared to be filled with humus.

Mode for Carrying Out the Invention

The invention will be explained in more detail, basing on exemplary protection from erosion of a two-meter-high scarp with the slope of 45%.

After levelling the slope surface of the scarp 1 with the well-known methods, a line was made on the crown of the scarp, at a distance of 50 cm from the upper edge 2 of the scarp 1. Along the line an anchoring ditch 3 of the depth of 30 cm was made. In the anchoring ditch 3 end of the geotextile roll 4 of a width of 300 cm was placed. Then end of the geotextile roll 4 was anchored in the ditch 3 and covered with soil. Next, the geotextile roll 4 was unrolled down to the foot of the scarp 1. Used a bidegradable geotextile, made of a mixture of wool and cotton, of a basis weight of 250-300 g/m ² in a dry state and containing grass seeds 5 inside, in the amount of about 10%-20% of weight. Then, similarly, next strips of the same geotextile 4 were placed and anchored with the minimum of 10 cm overlap. A typical spatial geogrid 6 was placed on the unrolled geotextile 4. The geogrid used was of the type in which a single leaf was made of sixty high-density polyethylene strips 7 of a width of 25 mm and a length of 3500 mm, ultrasonically welded 8 together, passing one another every 340 mm. After unrolling such leaf on a surface, a cell structure that is obtained has a width of about 260 cm and contains the cells 9, each forming an area of about 300 cm ² . The upper edge of the geogrid 6 was anchored in said ditch 3 with the use of anchors 10 made of steel wire of the diameter of 8 mm, U-shaped with a height of 400 mm, or J-shaped anchors with a height of 500 mm. Along the upper edge of the geogrid 6, the anchors 10 were placed in every second cell. The adjacent patches of the spatial geogrid 6 are connected by the U-shaped anchors 10 placed in every adjacent cell 9. The unrolled geogrid 6 patches, which are not situated on the edges, are fixed to the ground with the J-shaped anchors 11 using one anchor for each 1 .5 square meter of the covered surface. After careful anchorage of all geogrid patches 6, its cells 9 were filled with humus 12 with the surplus of about 2 cm and than the humus was sprinkled with water. If necessary, the geogrid 6 with the strips of larger length and width can be used, as well as with strips perforated or incised. To accelerate the pace of work, the ready-made equipment sets can be used which are adjusted to the specific slope through the choice of the basis weights of the geotextile 4 and the geogrid 6 parameters 6. Such equipment set contains a designation of a number of square meters of a land to be covered, adjusted amount of the geotextile 4 and a number of the geogrid patches 6 as well as correct number of the U-shaped 10 and J-shaped anchors 11 . The set prepared for area of 00 m ² of a typical embankments contains approximately 10 m ² (4 rolls) of the geotextile 4 that is described above, four patches of the spatial geogrid 6 described above, ninety U-shaped anchors 10 and eighty J-shaped anchors 11 .