Hi-tech route for Metro

By Lalit K. Jha

NEW DELHI, NOV. 17.

With the trial run of two gigantic tunnel-boring machines in Gwalior and digging up of a huge shaft here, the process of construction of underground passage for the upcoming Metro Rail has begun in right earnest here in the Capital.

The state-of-the art tunnel boring machines (TBMs) are due to begin work at three different locations here in April next and the task of digging up as many as 9 km of tunnel would be completed by 2003-end or mid-2004.

First of its kind in the country, the German-made TBMs have been brought to India from Bangkok at an estimated cost of Rs. 40 crores. At present it is being assembled and undergoing a trial run at a workshop in Gwalior.

The gigantic TBMs -- 70 to 80 metres in length, weighing 400 to 500 metric tonnes and 6.2 metre in radius -- is as long as four passenger rail coaches, said the DMRC Chief Project Manager (Metro), Mr. Mangu Singh.

Giving details of the machine, Mr. Singh said though it will move at a slow pace of 10 to 15 metres per day, the high-tech TBMs, which are internally airconditioned, take care of all the vibrations which can create disturbances in buildings above the surface. ``It will simultaneously create concrete structure inside the tunnel through a prefabricated structure,'' he said.

According to Mr. Singh, these TBMs have been tailormade to suit Indian conditions. While two of them are soft soil TBMs, for digging up tunnels between ISBT and Old Delhi and New Delhi railway stations, and Patel Chowk on Ashoka Road, the third one is rock TBM, for the tunnel passing below Chandni Chowk between two railway stations. ``These decisions were taken based on the study of the soil,'' he said.

These TBMs which will slowly move ahead in the tunnel after cutting the earth as deep as 24 metre below the ground at a slow speed of 10 to 15 revolution per minute, would automatically pass the excavated earth through an automatic system to a truck above the tunnel at a pre-determined location.

``The advantage of these machines are that dugup earth is taken out at one place only. Not only this, a small team of ten to 12 highly skilled people would complete the entire task. It is so sophisticated and vibration free that vehicles can easily move above the road on top when the work is in progress below,'' he said.

Right now, Mr. Singh said, the DMRC was making preparations for creation of a shaft through which these gigantic TBMs would be pushed below the ground. He said after trial runs at Gwalior, the TBM would be dismantled, transported to the Capital in parts and then reassembled here below the huge shaft which is 22 metre in width, 40 m in length and 18 m in depth. One such shaft is being dug up at Ashoka Road in Lutyen's Delhi.

Asserting that the DMRC was strictly following the guidelines and standards set by the National Fire Protection Association of the U.S., Mr. Singh said as a precautionary safety measure, cross passages at frequent intervals were being constructed between the two parallel tunnels below the ground, which would be normally separated by a distance of 12 metres.

Send this article to Friends by E-Mail

Section  : Other States
Previous : Dayawati Modi Award presented to Asha Bhosle
Next     : Yoga is his passion and mission