KONKAN - KONKAN - India
KONKAN RAILWAY CORPORATION LIMITED
KONKAN RAILWAY (KRCL) ROUTE
Fig 1.A typical KRCL stretch with narrow tracks & steep side slope
Fig 2 .Gabions for landslide mitigation constructed in 2001
Konkan Railway Project can be considered as one of the most prestigeous projects in the Construction Industry of India.The project was launched in 1989 and the track became operational in the year 1998.The 760 km line passes through complex terrains.In many of the stretches, the available space was restricted and the side slopes were very steep.This formidable terrain and the short construction period necessitated the use of several technological innovations. The construction and widening of the track called for large quantities of cutting in rocks of lateritic and basaltic origin.The exposed lateritic terrains were subjected to heavy rainfall and in the presence of water, the laterite loses all of its cohesiveness,strength and become very vulnerable to cause heavy slides and slips.This problem necessitated the provision of several landslide mitigation techniques like construction of proper retaining walls and rockfall prevention measures.
Maccaferri Gabion walls with stepped rear face were adopted in many vulnerable stretches of hill cuttings of Konkan Railway. Backfill soil was carefully selected ensuring the omission of clayey soil. Additional arrangements included provision of transverse drainage system, comprising of 2.9mm dia heavy duty PVC pipes per metre laid at a slope of about 1:20.to carry water away from the foundation. The foundation comprised basically of lateritic soil. Owing to the relatively high level of water table, the foundation depth was restricted to a minimum of 0.5m. At places where the foundation comprises of very fine clayey soil, Terram 1000 Geotextile was placed at the bottom of the Gabion Wall in addition to the backside in order to prevent the ingress of fines. Gabion walls were selected due to its flexibility, speed in construction and fine draining nature.