With a tunnel length of 18 kilometers, the Veligonda project near Hyderabad is one of the most challenging in India. The alignment of the tunnel passes under the “Rajeev Gandhi” nature reserve – well-known for its tigers. The aim of the project is to tap into the Srisailam dam with an underground tunnel, so that water can be diverted to drought-ridden areas when the dam threatens to burst its banks during the monsoon season.
A large Herrenknecht Hard Rock Double Shield is currently at work on the project. The 2,800kW TBM is boring the tunnel at depths of as much as 550 meters. In February 2012 an Indian tunnelling record was achieved: 525 meters of excavated and lined tunnel with in 29 days. The jobsite teams prove their endurance while they advance this long-distance tunnelling project meter by meter. approx. 14.5 kilometers where excavated until October 2017.
The tunnel with an inner diameter of seven meters is lined with hexagonal segments, four segments forming one ring. This is the largest tunnel diameter lined with this kind of segments. 47,000 segments in total are produced on the jobsite in a segment plant deliverd by Herrenknecht Formwork including carousel, curing tunnel and concreting station.