The railway network of India is one of the world's oldest and largest. Sections of this network are acknowledged engineering marvels. Notwithstanding this, geosynthetics are yet to play a significant role in the engineering of the railway track. There is great scope for geosynthetics to evolve safe, economical and sustainable designs for the railway track.
Soil erosion is a major concern considering the integrity of the sub-ballast and ballast layers may be affected by severe cuts arising due to weathering.Conventionally, stone pitching has been the preferred solution to reduce erosion. Availability of stones is posing a great challenge from an environmental and commercial stand point, it is imperative that alternate solutions should be utilized.
StrataWeb® provided along the slope surface helps to prevent erosion by effectively confining the top soil within its three dimensional frame. Locally available fertile soil can be used as an infill which can be further vegetated to provide a green finish, thus avoiding the use of expensive stones for slope protection. Installation is extremely simple and five times faster as compared to stone pitching.
Steep Slope/ Wall
Conventionally, a railway grade is raised either by constructing a RCC wall or an embankment with natural slopes. In the first case, the cost is high and construction is time consuming, while in the second case, large tracts of land has to be acquired which is prone to litigation, requires substantial time and can be expensive based on the region.
Strata reinforced soil solutions are very well suited for use in railway embankments. This is a proven technology the world over and has been extensively used by Strata on national highway projects in India. With the use of reinforced soil solutions embankments can be constructed faster, requiring less land footprint and with savings greater than 20% as compared to conventional RCC walls. Global design methods are well established for this technology and there are several Indian and international codes to support the design.
Embankment & ground improvement
One of the toughest challenges faced by railways is to prevent differential settlements along its track that can lead to operational issues such as speed reduction, constant downtime and frequent maintenance. Presence of soft soil along the railway track leading to differential settlements is always a major concern.
StrataWeb® is a well-established solution to improve the bearing capacity of sub-grades and significantly reduces differential settlements. Due to the principles of confinement, StrataWeb® distributes heavy loads uniformly over a larger area thereby reducing the pressure acting upon the sub soil of the embankment. StrataWeb® has been permitted for use in railways for ground improvement by RDSO in India and has been extensively used the world over.
Track bed stabilization
Constant maintenance and replacement of ballast layer due to loss of ballast material is an expensive activity resulting in frequent outages. The ballast layer is subjected to heavy vibrations that cause dislodging of the aggregates. Depending upon the nature of the sub-ballast and subgrade material
StrataGrid™ biaxial is ideal for reducing the loss in this layer. The apertures in the grid interlock the ballast material providing a stable and strong configuration. The grid is made of high quality poly-propylene which is extruded to provide high strengths at very low strain values and acts as a rigid mat below the ballast layer. The grid can be used effectively for new alignments as well as for improving the existing tracks. This has found wide application in railways in India.
StrataWeb® being the only 3 dimensional geosynthetic system, has the advantage of offering effective confinement of the ballast and sub-ballast materials. This not only reduces maintenance requirements but also offers a smoother and faster ride. Its reinforcement characteristics help improve the bearing capacity of the embankment on which the formation is laid.