The Central Secretariat- Mandi House line was fitted with instrumentation equipment
The upcoming 3-km-long Central Secretariat – Mandi House line has 1,600 instrumentation equipment fitted on various buildings along the alignment. They provide information on a range of parameters such as structural soundness of buildings and enable real-time web monitoring.
Earlier, these equipments were also used during construction of the AIIMS metro station on the Jahangirpuri- HUDA City Centre line.
“Some of these equipments transmit data directly to systems, which is then analysed, while others require physical readings to be taken,” said a senior official of the Delhi Metro Rail Corporation, adding that there are instruments of various types such as tilt plate, bio-reflex targets and crack meters.
“These instruments enable monitoring on a daily basis and the Delhi Metro receives a compiled report every fortnight,” the official said.
The installation of instrumentation equipment by the Delhi Metro is part of the safety measures undertaken prior to starting work on a corridor. A pre-construction survey is carried out along the alignment by a team comprising geologists, construction managers and structural engineers. This is followed by a construction survey (during the course of construction) and a post-construction survey after work is completed on the line.
“There is an in-built alarm system in the devices that detects trigger values and if found to be worrying, SMSs will be sent to five or six people to alert them,” said the official.
Readings are taken almost two to three times a day while work is in progress on a particular corridor.
“After work is completed on a particular corridor, the equipment is removed from most buildings. On those buildings where minor cracks are detected, the crack meters continue to function and transmit data,” said the source.
Regarding the soil excavated from Metro sites, the official said it gets transported to the various depots run by Delhi Metro in places such as Sarita Vihar, Shastri Park and Mundka.
“Many of these places are low-lying areas and the mud is being used to raise them. We have also supplied mud to build the base camp of the Rajasthan Police and for reinforcing forest land,” said the official.
“Nothing is given for private benefits but only for public interest,” the official clarified.
A total of 1,14,000 cubic metres of earth was excavated from the Janpath metro station alone during its construction.
“The amount of earth excavated is based on the number of rings on the Tunnel Boring Machine. If you cross 10 to 12 rings a certain quantity of soil is excavated,” said the official, adding 100 trips on average were needed to transport the mud. “Progress of the work is directly proportional to the amount of soil excavated.”
The TBM working on the Mandi House – Janpath section is expected to surface between April 17 and 20 followed by another one close to the end of May, said the official.