During 2006 to 2009, excavation slopes at sections 737th km + 700 — 738th km + 500, 730th km + 025 — 730th km + 650 (left and right) and the subgrade embankment slopes in inundated areas near the bridges over the rivers Don and Bogucharka were being underpinned. The slope reinforcement height amounted to over 12 m with maximum steepness of 1:1.5. Geospan GC volumetric geogrids made by Gexa – Nonwoven Materials OOO were used for reinforcement and erosion protection of the slopes (14,000 m2 of Geospan GC 30/20 and 8.000 m2 of Geospan GC 30/15). Needle-punched geotextile of 400 to 500 g/m2 density was used as Geospan GC’s underlayer, while granite macadam was used to fill the cells.
Examination of the slopes reinforced by Geospan GC volumetric geogrids revealed the following:
- The slope original shape intact.
- No trace of soil wash-out in the slope inundated part found, no trace of soil wash-out by precipitation and melt water found.
Based on the slopes condition examination results, it may be deduced that the geogrids may be used to increase reliability of erosion protection and secure the overall stability of motorway slopes.
