The Central Railway is contemplating usage of a relatively new concept involving concrete canvas to firm up the hillocks that are prone to landslides in the ghat section of Nagpur Division. The work is planned along side laying third-line in Teegaon-Chinchoda section of 17 kms that cuts through Sahyadri Ghats of Nagpur-Itarsi section. The area is treacherous as falling boulders from mountains abutting the tracks pose danger, particularly more during the monsoon season, for passenger trains.
The construction arm of the Central Railway zeroed on geotextiles for use in preventing boulders from falling off the mountains. Concrete canvas is basically known as Geosynthetic Cementitious Composite Mats (GCCMs) in technical term. At present, Railways is using the technology for extending life of track formations that could in long run cut down its maintenance costs. Railways are now deciding to hold trials in Nagpur Division by using concrete impregnated fabric, the technical terminology, and if successful in preventing slippage of loose boulders here, then same could be used in other ghat sections.
Railways were on lookout for reliable technique to minimise threats of disruption in ghat section and is preparing to start slope protection work. The construction division has decided to level the hillock surface before the fabric is affixed on it with help of screws. The thin film would be put up at certain height that would be decided at time of execution of work given the challenging conditions that exist in the ghat. Officials further added that at present it is difficult to estimate how much height they could go but given the high cost of this new fast setting concrete, Railways are determined to go all out for testing the utility of the fabric.
Once the concrete fabric is fitted it is then allowed to hydrate to form a thin transparent wall. Compared to conventional concrete, geotextiles offers use of ease and can be carried on site easily. They came in rolls similar to cable bundles and two persons can lift it without much effort and it is then rolled out and applied on the surface. The wall is then sprayed with certain quantity of water and then allowed to solidify, which is maximum 24 hours. Once settled a thin transparent wall is formed and it is fire proof and beyond that water proof that is basically requirement in this section. Another advantage of geotextiles is that they are quite durable and have low carbon footprint.
The ghat receives very high intensity rainfall that leads to seepage of water in the mountains leading to loosening of soil that holds big boulders. CR officials said they are going to use this technology for very first time and thereafter monitor its performance. One concern among Railways engineers is to determine whether the concrete wall managed to withstand shocks from passing trains. Listing the advantage CR’s engineers said that in comparison with traditional concrete use, the concrete canvas can be rolled out at a rate of 4002/hour, nearly 10 times faster, thereby reducing time on site time. Given it chemical component, even under harsh ultra violet rays the concrete fabric does not lose shape and hence has long life. The maintenance is almost negligible that is added advantage and importantly it arrests growth of weeds inside the concrete wall.