A Possible hazard to the Road Abutting properties along the alignment of Chennai’s Underground Metro Rail:

A Possible hazard to the Road Abutting properties along the alignment of Chennai’s Underground Metro Rail:

Chennai’s underground metro system is under construction during the period from 2011 to till date.

The Anna Salai alignment has many existing multi-storeyed buildings on both the sides of the alignment.

The Usual settlement rate of a building:

            The foundations of buildings normally take a long time to settle. Hence the rate of settlement will be in the range of cm/year. The average rate of settlement for most of the buildings shall be in the range of 3 cm/year.

The Tunneling process in the underground metro :

The Tunneling process to create the underground rail path is done by means of tunnel boring. Hence the earth which got removed is disposed immediately to distant sites. Now a vaccum is created in the middle zone of the properties abutting the road above.

This Vaccum loosens the stratum which is very near to the periphery of the front end foundations of the road abutting properties. This loosening phenomenon will tend the front end foundations to have a higher rate of settlement than the rear end footings. Hence the buildings abutting the alignment of the underground metro are subjected to a differential settlement.

This differential settlement can cause a shear failure along the vertical height of the building either at the midpoint or at any point depending upon the rate of settlement. 

The Vibrative Shear force caused due to the moving train:

In addition to the differential settlement, the moving train inside the tunnel exhibits a vibrative force to the soil strata around the tunnel. This force is also transferred to the nearest footings of the abutting buildings.

Hence there is a real hazard to the abutting multi-storeyed buildings as well as normal buildings. The failure may happen at any time in the nearest future, but we cannot exactly forecast the date of failure. Hence Engineers concerned in this project are requested to take remedial measures accordingly at the earliest.

The Failure of Road pavement crust in the Thirumangalam alignment:

The following photographs shows that the road pavement above the Thirumangalam metro alignment are wavering.

 The Road Pavement got wavered because of tunnelling action. Anyone who uses a two-wheeler can easily realise the wavering motion of his bike while manuevering this particular road.

This gives us a warning sign that the road plate above the tunnel may fail at anytime at many locations throughout Thirumangalam to Anna nagar Round about.

Hence the concerned Engineers are requested to take proper precautions as soon as possible.

Recommendations to Real Estate people dealing properties abutting underground metro rail:

The Real Estate people who are involved in dealing the transactions of the properties which are abutting underground metro rail tunnel should be aware of the possible future hazards.

So, they are requested not to recommend any transactions for the buildings which are expected to fail. Even the land value for those properties will come down to zero because the land abutting the Underground Metro cannot be used for livelihood in the future.

Hence Evacuation from these properties could be the right solution.

---An Article by Bharath Dhanasekaran ----