Chennai Metro has initiated preliminary work on phase-2 including a study to find out noise and vibration levels that may arise during construction of the 118.9 km line and operation of trains and their effect.
Based on the study, Chennai Metro Rail Ltd (CMRL) engineers will conduct a field survey of buildings along the corridors to take up mitigation measures like installation of noise muffling equipment and evacuation of people living nearby as well as designing of tracks and stations to reduce noise pollution. Construction of the first 52 km is expected to begin later this year and is likely to be ready by 2024.
CMRL has floated a tender to appoint a firm to do computer simulations to forecast the levels of noise and vibration for three corridors during construction and operation. The study, crucial to assess environmental impact of the project, will follow Federal Transit Administration guidelines developed by the US transport department.
Officials said a computer software will simulate conditions in the construction and operation phase including soil conditions which decide the speed at which tunnels can be drilled and pile foundation laid. During operations, track systems, train speed and frequency, which can cause pollution, will be considered. The levels will be studied mainly in densely populated and high traffic areas.
Phase-2 lines will cut across Madhavaram, Porur and Poonamallee in the suburbs and Purasawalkam, Royapettah, T Nagar, Kodambakkam, Mylapore, CMBT and Anna Nagar.
Former CMRL director R Ramanathan said reducing speed of tunnel boring machines and installing rubberised material under tracks are among the measures normally adopted to minimise noise. “There may be hospitals and laboratories that could be affected during tunnel boring and train operations…”, he added.
The contractor during construction of tunnels is expected to appoint experts and conduct a study to plan measures like vacating people in the surrounding area. When phase-1 train operations began, a few Shenoy Nagar residents complained of noise and vibrations leading to cracks on walls of houses.