Soil nailing technology has come to the aid of the National Highways Authority of India (NHAI) for the stablisation of steep slopes along the Kazhakuttam-Karode bypass corridor of the National Highway 66.
The NHAI had used the technology for the first time in the State when embankment in the 26.79 km Reach I from Kazhakuttam-Mukkola near Upper Primary school, Kuzhivila slipped during the four-laning works.
Following the success in Kuzhivila and as it was found to be durable and cost-effective, the NHAI is using the soil nailing technology to reinforce slopes which are more than four metres high.
For slopes up to four metres high, the NHAI is constructing retaining wall for stability and to prevent caving in of the earth. Metal rods of 25 mm to 32 mm are inserted into the pre-drilled hole in the soil at inclination of 10 to 20 degrees. It is then cement grouted under gravity or low pressure and geotextiles is applied to ensure stability.
The NHAI is using the expertise of the IIT Chennai for the soil nailing technology in the bypass corridors that is being four-laned through EPC mode.
In the 16.2 km Reach II from Mukkola to Karode on the Kerala-Tamil Nadu border, the NHAI is using the soil nailing technology widely to protect the embankments above a height of 4 metres.
A top NHAI official said the EPC contractor L & T Constructions has been asked to use the soil nailing technology as the green field four-lane concrete highway being developed traverses through villages that has undulating terrain.
