ABSTRACT
Underground constructions underneath roads in busy areas of urban city can bring out many unexpected challenges. One such challenge was faced by Delhi Metro Rail Corporation Ltd (DMRC) during construction of underground RCC box tunnel at Najafgarh area of Delhi urban city, where the adjacent buildings were as near as 1.5 m from the soldier piles line. During rains soil piping was observed in the thin area between building lines and soldier piles lines which caused excessive settlement in the ground resulting in formation of sink hole, partial collapse of the building, cracking and tilting in the buildings, damage of roads and utilities. An immediate technical solution was required. This paper highlights the case study of challenges and complications encountered during construction of underground RCC box tunnel on busy carriageway road with simultaneous instrumentation monitoring of adjacent building while maintaining smooth plying of traffic.
