Performance assessment on influence zone of existing structures for metro construction

Abstract

The current mega cities such as Kolkata, Mumbai developed over centuries from even before colonial times and they now consist of old parts and new parts. Though underground construction even in the new parts is not an easy task, in the highly built-up old areas with narrow lanes, going underground while saving what exists above ground is a daunting task. Such a situation arose while taking one of the lines of Delhi Metro through the area of “Old Delhi”. Monitoring the ground features, including old building and monuments during construction became essential. Underground construction, as carried out for East-West metro Kolkata or Mumbai metro line 3, demanded extensive monitoring to assess ground movement and displacement depending upon depth and volume of works underground, soil conditions and foundations of existing buildings and utilities. The paper highlights geology, protecting existing structures, ground movement, construction method, and safety aspects in planning and construction.