With foam flowing out and roads caving in, it is fair to say commuters of Chennai have been quite discomfited with construction on the underground stretches of the Chennai Metro Rail. As of now, about 80 km of phase II of the project has been planned underground to reduce the amount of land to be acquired.
Despite the numerous incidents of foam emerging on the road and cave-ins, experts still think it may be good for the city due to lesser land requirements. But since an extensive part of the city will have underground construction, experts say, work on it should begin after a meticulous assessment of soil quality.
R.G. Robinson, professor of geotechnical engineering at IIT-Madras, said the city has varying types of soil but work can still be carried out efficiently if proper soil investigation is carried out. “Some areas have clayey and some others sandy soil. But if the officials do good profiling of the soil, then it should not be a problem. Also, the right type of cutter head must be used in the tunnel boring machine and right pressure should be employed while boring,” he added.
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Also, the placement of the watertable should be noted, he added.
K.N. Krishnamurthy of Indian Road Transport and Development Association said the right contractor must be appointed to ensure the work isn’t delayed. “What happened with Gammon India, the contractor who delayed the project and eventually got terminated, should not be repeated. The officials have had a learning experience from phase I of the project; so, they can predict the course of phase II,” he added.