Project for ecological restoration of a mountain slope in the city of Sochi, Krasnodar Territory, Russia: use of ecological bags (geotubes) for greening and strengthening slopes.

Project Background

In 2020, the Department of Natural Resources and Environmental Protection of the city of Sochi made a decision to carry out ecological restoration of the damaged mountain slope following the landslides. To prevent further erosion, restore the vegetation, and ensure the stability of the slope, it was necessary to apply modern geosynthetic solutions. The contractor won the bid for the supply of ecological bags and the construction of slope greening projects, and selected a professional supplier of geosynthetics. The contractor reinforced approximately 35,000 square meters of the mountain slope using a system based on ecological bags (geotubes). This system included: polypropylene ecological bags with high resistance to UV radiation, a special plant mixture (seeds of perennial herbs and shrubs, nutrient soil), as well as a drainage layer made of geotextile. The ecological bags were arranged in a brick-laying pattern, secured with anchors, and created a long-lasting green surface.

Ongoing tasks

For this project, a specialized assessment of the stability of the mountain slope after reconditioning was conducted. The technical requirements clearly specified that the eco-bags used must be tested for seam strength, water permeability, and interaction with the plant substrate. The engineering company required tests to be conducted for shear resistance at the interface between the ecological bags and the underlying geotextile, as well as between the bags themselves, to ensure compliance with point 5's requirements. 2.3 Technical conditions: "The interface surface between the environmental bags and adjacent materials must provide a friction angle of at least 13 degrees and a bonding force of at least 12 kPa, or an equivalent combination of Coulon-Morse strength parameters within the limits of tested normal loads and movements."

Solution

The supplier completed all the required interface shear tests and provided complete data confirming that their eco-bags significantly exceed the requirements of the specification (the actual friction angle was 14.7 degrees, the coefficient of friction was 14.2 kPa). All test results were provided on time, which did not affect the construction schedule.

The main problems for the supplier were the complex logistics of delivering materials to the mountainous areas of Sochi (limited access roads, need to use small-scale transportation), as well as the need to carry out work in a humid subtropical climate with frequent rainfall. To complete the work on schedule and within the budget, the contractor used every favorable weather day, increasing the length of shifts and installing as many ecological bags as possible. The supplier's logistics department worked closely with the contractor and transportation subcontractors, ensuring the timely delivery of all materials to the site.