Effective Track Reinforcement in Extreme Conditions
In the permafrost bogs of Russia, Neoloy®Geocells provide track reinforcement, increasing bearing capacity, speed and loads
Russian Railways (RZhD) is the government-owned railway company of Russia, and is one of the largest in the world, in terms of employees (1.2 million), traffic, rolling stock and length of track.
Challenge – Reinforce Soft Permafrost Soils
In the Arkhangelsk Province of the RZD (Russian Railways) the rail embankment and structural support layers, traversing through permafrost bogs, are subject to steady deformation. Neoloy Geocells were deployed to strengthen the track formation layers in “ailing” sections by forming a semi-rigid beam that provides uniform rigid support of the upper structural layers and reduces settlement and accumulated degradation caused by the weak subgrade.
Neoloy Geocell Solution – Increases Speeds & Loads
After removing the old track and ballast, 15 cm of Neoloy was installed in the sub-ballast layer. Infill consisted of a sand-gravel mixture, with 6-10 cm compacted overfill. The infill was dropped from a rail chute at a height of several meters without damage to the stiff cell walls. A new layer of 60 cm ballast, along with new sleepers and rails were laid down on the top layers.
The Head Supervisor of the Geotechnical Evaluation Center of RZD, Vitaly Leonyuk, stated that: “the Neoloy reinforcement subbase layer prevents deformation in the embankment and structural layers as a result of the dynamic loading” and “it enables trains to pass over these problematic sections at higher speeds and at heavier axle loads.” RZD plans to install 68 thousand square meters of Neoloy Geocells in the rehabilitation of 13.6 km of problematic track in this Northern region.
• Operational: 40% heavier loads and 30% faster speeds
• Engineering: Increased bearing capacity, reduced structural layer thickness, prevented aggregate attrition
• Material: Long-term resistance to creep, oxidation, temperature extremes, UV light
• Economic: Lower initial construction costs, long-term ballast and track durability, improved safety and reliability, frees maintenance budgets for new track construction.