Due to the insufficient margin of safety in the area under consideration, it was decided to reinforce the pavement structure with the help of a separating reinforcing layer made of Geospan TN 50 geotextile material.
After the work, this design fully complies with the provisions of the technical regulation documents in force in the road industry, in particular, it meets the criteria of ODN 218.046-2001 (strength - elastic deflection, shear resistance, bending tension and frost resistance) with the accepted design data (Road building climatic zone 3/2, 1 type of terrain, subgrade soil - heavy loam Wp=0.62, load 115×1.3=149.5 kN/m, road category II, service life - 14 years, estimated number of load applications per lane over the service life of 500 thnd vehicles).
The woven polypropylene geotextile material Geospan TN 50, used as a separating and reinforcing layer, produced according to the standard of the organization agreed by the Federal Road Transport Agency, meets the recommendations on the properties of Annex D to SP 34.13330.2012, in particular, on the required tensile strength for roads of categories I through II - at least 40 kN/m.
Thanks to the use of this material, better working conditions were provided at the contact of the layers and clogging of the drainage layer was excluded. An additional effect is the reduction of uneven heaving, which is the result of the impact of the reactive pressure of the Geospan TN 50 material at certain points of the subgrade, where the heaving exceeds the average value for the site.
The presented design of the pavement also complies with the provisions of interval 5 of ODN 218.046-2001 (drainage) in case the filtration coefficient of the base layer material (crushed stone mix C4) exceeds 1 m/day.
