Underground Construction - Considerations and Challenges

The article summarizes the challenges and considerations during planning, execution and commissioning of underground sections of metro. The work of fixing the alignment starts with fixing up the location of the station box, availability of the land in the close proximity of major origin/destination points or nodes which are dense passenger traffic junction is important. There are the instances when separate vacant land at these locations is not available, and in all such cases stations are planned below roads. Consideration of buildings nearby, no. of trees affected, possible traffic diversion, soil strata, utilities, access to the residents nearby are few points which are kept in mind the location of the station. Suitability from point of view of traffic integration is also a main criterion for fixing station locations. Stations are planned in such a way so as to be near established traffic interchange nodes so that they fit in the existing transport network and provide seamless intermodal transfer.


Adequate width of road (in case of station being in the middle of road), Availability of land for locating entry exit structures Parking and Dispersal facilities, DG set, Fire water tank, ventilation shafts and minimal property acquisition are some of the other challenges which are faced while fixing the location of the station. Inter station distance to be about 1-km. Stations are not located on gradients, and are always to be on horizontal alignment. Alignment should be straight to the extent possible, in case the station must be located on curves due to other pressing demands, the curve should not be sharper than 1000-m radius. Although stations are preferred to be close to road intersection, the effort is to locate them not directly over the intersection so that the station structure does not hamper the flow of traffic.