The Bangabandhu Sheikh Mujibur Rahman Tunnel (or Karnaphuli Tunnel) is a 3.4 km long, twin underwater road tunnel in the port city of Chattogram, Bangladesh. It is the first under-river road tunnel in South Asia. The tunnel has a 10.6 m internal diameter and has a minimal clearance to the Karnaphuli Riverbed of 31m. Geotech Survey Experts is very fortunate to be the first tunnel operator in South Asia and to be associated with it.