Construction of Bangabandhu Sheikh Mujibur Rahman Tunnel beneath the Karnaphuli River is going on in full swing as more than half of the work has already been completed.
The Bangabandhu Tunnel, the country’s first and the longest in South Asia, 31 meters below the Karnaphuli River, is being constructed with a monster-shaped Tunnel Boring Machine TBM 95 meters in length.
The tunnel, the country’s first of its kind and the longest in South Asia, 31 meters below the Karnaphuli River, is being constructed with a monster-shaped Tunnel Boring Machine TBM 95 meters in length.
It is expected to open for public in December 2022, Project Director (PD) Engineer Harunur Rashid Chowdhury told Bangladesh Post in January this year.
An official at Bangladesh Bridge Authority (BBA) said, “A tunnel boring machine (TBM), also known as a "mole" is being used to excavate the Bangabandhu Tunnel consists of a shield (a large metal cylinder) and trailing support mechanisms which is using Shield Driven Method SDM.”
He said, “A huge rotating cutting wheel is located at the front end of the shield. Behind the cutting wheel there is a chamber where the excavated soil is either mixed with slurry or left as-is Earth Pressure Balance or EPB shield. Behind the chamber there is a set of hydraulic jacks supported by the finished part of the tunnel which are used to push the TBM forward. Once a certain distance has been excavated (roughly 1.5–2 meters (5–7 ft)), a new tunnel ring is built using the erector.”
The four lane tunnel route will pass through under the river close to Naval Academy at Potenga of Chattogram city on one side and Korean Export Processing Zone (KEPZ) and Karnaphuli Fertilizer Company (KAFCO) at Anowara upzila on the other side.
Engineers said that the construction works so far involves 1,228 meters long excavation of soil with 614 rings installed. The tunnel is 4.9-meter-high and 11.4 meters wide.
If favorable weather prevails and no natural calamities take place the installation of rings in the two tubes of 2450 meters each will be completed by next May or June next, they said.
Officials inform, the distance between the two tubes is about 12 meters inside the tunnel. There will be three cross passages between the two tubes, so that it can be accessed when needed.
The emergency exit will be placed at seven places at the bottom of each tube. There will be enough air and oxygen ventilation system inside the tunnel.
Necessary rescue teams and special fire service teams will also be kept on standby. In the meantime, the acquisition of 383 acres of land for the tunnel’s approach roads has also been completed.
An approach road of 4.89 kilometres alongside 740 meters of bridge linking the tunnel in Anowara and 500 meters in Potenga is being constructed.
Prime Minister Sheikh Hasina and the Chinese President Xi Jinping laid the foundation stone of the tunnel on October 14, 2017 while PM Hasina inaugurated the boring work of the tunnel in February last.
The estimated cost of the tunnel is Tk 9,880 crore, where Chinese Exim Bank will provide Tk 5,913 crore. The Government of Bangladesh is arranging the rest.
Chinese firm ‘China Communication Construction Company Ltd (CCCC), has been appointed as consultant for the tunnel.
The tunnel is expected to make communication between Chattogram and Cox’s Bazar easier alongside reducing traffic congestion on two bridges over the Karnaphuli River.
