Geosynthetics play an important role in today’s railway infrastructure ensuring stability, durability and effectiveness of railroads. These materials comprise a wide range of products, such as geotextile, geogrids, geomembranes and others that are used for various purposes including subgrade reinforcement, drainage, erosion protection and decrease in load impact.
Contents
Geosynthetics history and development
Geosynthetics types and application
Examples of successful use of geosynthetics
Geosynthetics history and development
Geosynthetics usage started in the second half of the 20th century when development of new synthetic polymers began. Geosynthetic materials are those that have at least one component made of synthetic or natural polymers by way of fibers, flat filaments, strips or 3D structures.
R & D companies and manufacturers were engaged in concentrated research that enabled a very active development of geosynthetics production. Since then, geosynthetics technologies have seen a considerable evolutionary growth enabling their wider application in various construction areas including railway construction.
Geosynthetics types and application
Geosynthetics are divided into several types, with each allowing solution of a considerable number of essential issues in implementation of railway projects.
Geotextile
- Description: Geotextile is a nonwoven or woven material used in soil reinforcement, separation, filtration, strengthening and protection.
- Application: Geotextile use in railroad construction covers soil reinforcement and prevention of mixing of soil layers resulting in increase in subgrade stability. It is also used for embankment erosion protection and stabilization.
Geospan GT PP geotextile is one of the leading products in Geospan range. This material is loom-made of strong polyester fibers and is used in road pavement reinforcement, soil base strengthening and layer separation. Geospan PET is another woven geotextile brand made of polyester fibres. Geospan PET is used in construction of weak-based embankments and nonstandard-sloped embankments.
Geogrids
- Description: Geogrids are net structures, normally made of polymers, that are used in soil reinforcement.
- Application: Geogrids are used for embankment reinforcement and increasing the soil bearing capacity. In the railway construction context, this aids in railway settlement decrease and increase in resistance to train loads.
Volumetric geogrids are represented by Geospan GC (GCP) in Geospan range. It is made of strong polymeric fibers and can be perforated for applications requiring enhanced draining capacities in geogrid filling plane.
Geomembranes
- Description: Geomembranes are water impermeable layers made from synthetic materials that are used in waterproofing.
- Application: Geomembranes are used in railway structures to prevent water penetration into the embankment so that the soil wash-out is avoided and the deformation risk is lowered.
Geospan GT PP M is one of the geomembranes in Geospan range. It is a geosynthetic material with membrane properties, consisting of two laminated layers of woven geotextile.
Geomats
- Description: Geomats are net structures made from strong polymeric yarn.
- Application: Geomats are used in railway infrastructure for better load distribution and soil wash-out avoidance.
Geomats are represented by Geospan SL in Geospan range. They are effectively used for protecting embankment slopes, excavations, bridge abutments, including those in railway construction, against water and wind erosion.
Geosynthetics use benefits
Geosynthetics use in railroad construction enables solving a great number of essential tasks. The most important of them are:
- Increase in stability and durability. Geosynthetics aid in considerable improvement of the subgrade stability and extension of the rail road service life. This is achieved by soil reinforcement, drainage improvement and erosion prevention.
- Cost effectiveness. Geosynthetics use allows reduction in railway construction and maintenance costs. This relates to less earth works, better drainage and a lower repair requirement.
- Eco safety. Geosynthetics contribute to lowering the adverse influence on environment. They aid in soil wash-out prevention, water pollution risk mitigation and natural landscapes safeguarding.
- Performance improvement. Geosynthetics use allows better performance of railways including their bearing capacity, resistance to settlement and vibration. This is particularly important for high-speed rail roads and heavy-traffic sections.
Examples of geosynthetics use
Moscow – Saint Petersburg high-speed railway. Geotextiles and geogrids were used for the embankment reinforcement and the drainage improvement in this section. This allowed considerable reduction in construction time and improvement of the railroad performance.
Siberia – Far East railway line. Geomembranes and geomats were used for protection against moisture and slope reinforcement under conditions pf complicated terrain and poor soils. This enabled reliable operation of the railroad in aggravated climate environment.
Conclusions
Geosynthetics play a key role in the current railway infrastructure securing its stability, durability and effectiveness. They allow better performance of railways, lower construction and maintenance costs and lower adverse impact on environment. Given the constant growth of transportation loads and climate conditions aggravation, geosynthetics use becomes more and more justified making it an integral part of modern railway projects.
