Dubai: Dubai Municipality on Tuesday revealed the details of the excavation for the Deep Tunnel Storm Water System for Airport City-Expo 2020 which will begin in December.

The mega tunnel project will offer a long-term solution for rainwater drainage for 100 years to come in Al Maktoum Airport area, the Expo 2020 area and the nearby urban complexes.

The announcement about the massive drilling work beginning in December was made after a delegation visited China to inspect the manufacturing of the custom-made digging machine to be used for one of the most vital and strategic projects in the emirate.

A delegation from Dubai Municipality headed by its Director General, Dawood Al Hajiri visited the Chinese city of Guangzhou to learn about the stages of manufacturing of the digging machine. Dubai Municipality

Led by Dawood Abdul Rahman Al Hajiri, director-general of Dubai Municipality, the delegation visited the Chinese city of Guangzhou to learn about the stages of manufacturing of the digging machine, the municipality said in a press release.

The civic body said the drilling machine is expected to arrive at the site in October. The excavation will begin in December. The project will be covering an area of 490 square kilometres, which is almost 40 per cent of the entire urban area of Dubai, it said.

Al Hajiri and the accompanying delegation reviewed the quality standards in the factory in Guangzhou and the production efficiency procedures as well as the technical specifications that characterise the drilling machines.

The project was launched in October last year and is due to be completed by September 2020, as Dubai Municipality is racing to complete the project before the emirate hosts the World Expo 2020.

Dubai will be purchasing two large Tunnel Boring Machines (TBM) for drilling deep tunnels for the project. These machines will be the largest in the region used for digging tunnels transporting storm water.

10m-diameter tunnel

Al Hajiri said TBM 1 will begin its drilling work from the starting of the seventh intersection on Shaikh Zayed Road for a distance of 2.4km towards the sea up to the location of the main pumping station, then be dismantled and reassembled to move from the seventh intersection until the eighth intersection along 1.7km. In parallel, the second TBM drilling machine will start work from the Expo intersection on Jebel Ali-Al Lehbab Street for a distance of 5km and will continue until the eighth intersection on Shaikh Zayed Road, he said.

Al Hajiri said manufacturing and installation of one device will take 364,000 man hours.

The finished internal diameter of the tunnel will be 10 metres and the cutting diameter of one TBM machine will be 11.05 metres. The average daily drilling will be 19 metres per TBM.

“The drilling will be done in two types of soil — the weak rocky soil and clay soil with an average depth of 42 metres. The tunnel with a diameter of 10 metres will consist of eight concrete segments per ring, each 35cm thick. There will be two segment types — 1.6m and 2m wide and each piece will be weighing seven tonnes. These pieces will be fixed by iron pegs and sealed with epoxy (resin),” said Al Hajiri.