NEW DELHI: The Delhi Metro Rail Corporation (DMRC) has constructed over 50 km of underground lines across the National Capital Region in its Phase III maintaining the high standards of caution in dealing with the age-old heritage sites in the national capital.
Delhi Metro's Violet Line, also known as Heritage Line has a 5.17 km long underground corridor between ITO and Kashmere Gate comprising of four stations – Delhi Gate, Jama Masjid, Lal Quila and Kashmere Gate which was opened on 28 May, 2017.
The Line with 34 stations connects Kashmere Gate with Raja Nahar Singh.
In 2015, during the tunneling work of the Metro near Kashmere Gate a heritage structure collapsed partially. The iconic 117-year-old structures suffered damage as the underground tunneling had weakened its foundation.
According to officials, the sewer line began to leak causing the soil to weaken. Following the incident, officials pledged to repair the damaged structure.
A unique technique which included 30 Tunnel Boring Machines (TBM) was used in the underground lines in Phase III for the first time ever. "About 30 Tunnel Boring Machines (TBM) were used for this purpose.
The use of so many TBMs was perhaps the highest ever used anywhere in the world for a metro project. At four different locations, the new tunnels passed below the already operational Metro tunnels of the network," a DMRC spokesperson told this newspaper.
In many other areas, especially in the Old Delhi, the tunnels also passed below the centuries-old buildings and other structures of historical importance. The DMRC said that elaborate instrumentation was done while carrying out these activities to ensure that there was no damage to the structures above.
“Building Condition Surveys were conducted wherever possible and monitoring instruments were installed in these buildings to keep track of their condition during the tunneling process,” the spokesperson added.
Long term damage
St. James Church, built-in 1836 AD at Mori Gate is one example where the Kashmere Gate metro line is just five meters away from the building. At the time of construction of the metro, the DMRC had to convince the church authorities and Indian National Trust for Art and Cultural Heritage (INTACH) was also taken into consideration for going ahead without any damage to the heritage site.
“We had suggested the DMRC to use glass telltale which is like a slide during the construction. This was installed around the walls of the church so that in case of cracks, prevention was taken. The DMRC also recorded the vibrations during the making and running of the metro,” said Ajay Kumar, director (projects) INTACH.
This, however, could not relieve the church stakeholders from fearing long term damage to the 182-year old heritage site. Even though the DMRC had shared a study underlining the vibrations before and after the movement with the church authorities at that time, the latter is still wary of the long term impact on the church structure due to the everyday vibrations caused by the metro.
“DMRC indeed shared the details of their study after reading the impact of movements and glass markers with us but our concern is that the metro is just five meters away and when it passes through we feel the shudder in our church during the everyday routine...They shared the correct figures but on a humanitarian ground there was a need of their help in saving the church from the long term impact of the metro movement. We could not receive any reply on this end,” Kamal Baluja, chairman, Church Conservation Committee said.