The National Capital Region Transport Corporation (NCRTC) has started microtunneling work at its under construction Anand Vihar RRTS station for utility diversion work.
Keeping public convenience in mind, the NCRTC said it had chosen the microtunneling technique for diverting the existing interceptor sewer line of the Delhi Jal Board at the Anand Vihar RRTS (Regional Rapid Transit System) station site, which was infringing the RRTS corridor at the location.
Microtunneling is a trenchless underground tunnel construction technique generally used for constructing smaller tunnels for utilities diversion such as drainage pipelines to minimise the public inconvenience caused during the construction.
The technique allows free public movement in the area and is mostly adopted in places where footfall is quite high and trenching is not advisable as the extraction of debris causes blocking of passages restricting people’s movement. It is also very helpful for preserving existing infrastructure from any physical damage or alteration, the NCRTC said.
The NCRTC stated it is using a microtunnel boring machine, which follows the proposed diversion alignment with the help of a guidance system and uses pipe jacking method for laying the pipes behind the shield while moving forward.
“About 600-metre-long interceptor sewer line of 900 mm diameter high capacity non pressure (NP-4) concrete pipes will be laid at a depth of about 6 metre below the ground surface,” the NCRTC stated.
Reliable method
“Microtunneling is an efficient, fast and reliable way for installing RCC or concrete pipelines of various diameters below highways, railroads, runways, ports and environmentally sensitive areas without disturbing the surface activities and users,” it also stated.
The Anand Vihar RRTS station site is one of the busiest commuter transit hubs with a huge daily footfall as it is surrounded by a metro station serving two metro lines, a railway station and two ISBTs – one at the Delhi side and the other at Kaushambi on the U.P. side.
It said that construction activities at Anand Vihar are under way in full swing with the work of launching shaft of tunnel boring machine, measuring 20 m in length and 16 m in width, according to the NCRTC.
Longest tunnel section
“Two tunnel boring machines will be lowered in the launching shaft to bore RRTS twin tunnels from Anand Vihar towards Sarai Kale Khan to construct around 3 km tunnels. It will be the longest tunnel section between any two stations amongst the available metro systems in the country,” the NCRTC also stated.