TBM Kolli broke through on August 29 after completing a 903m drive from Ayanavaram Station to Otteri Station. Operated by Tata Projects Ltd, the TBM was launched on July 11 last year. It is Tata’s sixth breakthrough [https://www.tunnelsandtunnelling.com/news/breakthrough-on-chennai-metro/] under contract TU-01 and the seventh for the Phase II project.
The tunnel section between Ayanavaram and Otteri is the most complex under the TU-01 contract. In the first 500m, TBM Kolli had to negotiate a 220m radius curve and in the last 200m a 280m radius curve. The tunnel drive passed through densely-populated areas and there were more than 100 bore wells along the alignment.
Chennai Metro Rail’s Phase II expansion comprises three corridors over a total length of 116.1km.
Ayanavaram and Otteri stations are part of the 45.4km Corridor 3 which runs north to south across Chennai from Madhavaram Milk colony to Siruseri Sipcot. It will have 28 underground stations and 19 elevated stations.
Corridor 4 is a 26.1km east-west alignment connecting the beach front from Light House Station to the Depot at Poonamallee. It will have nine underground stations and 18 elevated stations.
Corridor 5 also begins at Madhavaram Milk colony and connects through Koyambedu, Porur, Alandur and other residential/commercial development of the city to Shollinganallur. The 44.6km line will have six underground stations and 39 elevated stations.
