CHENNAI: A sink-hole that suddenly appeared on Anna Salai road on Sunday afternoon devoured an MTC bus and a car when the road suddenly caved in at around 2:03 pm. The sink hole was 0-5 meters wide, 0-10 meters long and had a depth of 0-2 meter.
Passengers of both vehicles were immediately rescued by members of Chennai Metro Rail Limited (CMRL) and contractors, and the vehicles were lifted by a crane deployed by CMRL. Traffic was immediately diverted from the affected area to ensure vehicular movement.
CMRL is in the process of construction of phase 1 of Chennai metro comprising 48 km of underground, of which 46 km underground work is complete and less than 2 kms tunnelling remains between thousand lights and DMS which is in progress.
The basic cause of Sunday's incident, according to the CMRL is due to existing loose soil pockets along the tunnelling alignment where the tunnel boring machine (TBM) is operating. CMRL has a strict instrumentation and monitoring of settlement/deflection due to the ongoing tunnelling work.
The monitoring point has been installed throughout the tunnel alignment at a 10 meter interval. Continuous reading is taken every 6 hours to cross check any development done. The recent reading was taken around 2 pm just before the incident and there was no settlement recorded while taking the reading.
Inspection and restoration work of the affected area has been undertaken in full swing and traffic is likely to resume by Monday morning. Post restoration, the road will be safe for travelling