Dubai Municipality officials will be deploying Chinese tunnel boring machines (TBMs) for the implementation of the deep tunnel storm water system being developed as part of Airport City-Expo 2020 Project, one of the most vital and strategic projects in the emirate.

A delegation headed by director-general Dawood Al Hajiri visited the Chinese city of Guangzhou to learn about the stages of manufacturing of the machines, said a statement from Dubai Municipality.

The machines are expected to arrive at the site in October and the excavation will begin in December.

The project will be covering an area of 490 sq km, which is almost 40 per cent of the entire urban area of Dubai, said the statement.

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 2020 World Expo, said the statement from the civic body.

Dubai will be purchasing two large TBM machines for drilling deep tunnels for the project. These machines will be the largest in the region used for drilling tunnels that will be used for the purpose of transporting storm water, said Al Hajiri.

"TBM 1 will begin its drilling work from the starting of the seventh intersection on Sheikh Zayed Road for a distance of 2.4 km towards the sea up to the location of the main pumping station. It will then be dismantled and reassembled to move from the seventh intersection until the eighth intersection along 1.7 km," explained the top official.

"In parallel, the second TBM drilling machine will start work from the Expo intersection on Jebel Ali-Al Habab Street for a distance of 5 km and will continue until the eighth intersection on Sheikh Zayed Road, stated Al Hajiri.

According to him, the manufacturing and installation of one device will take 364,000 man-hours. "The daily energy consumption of the first device will be 64 MW taking the total consumption in 12 months to approximately 20,156 MWh. The second device will have a daily electricity consumption of 58.738 MW taking the total consumption in 14 months to 21,380 MWh," he stated.

Al Hajiri said the finished internal diameter of the tunnel will be 10 m and that the cutting diameter of one TBM machine will be 11.05 m, while the average daily drilling will be 19 m 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 m," noted the top official.
 
"The tunnel with a 10 m diameter will consist of eight concrete segments per ring, each 35 cm thick. There will be two segment types – 1.6 m and 2 m wide - and each piece will be weighing seven tonnes. These pieces will be fixed by iron anchors and sealed with epoxy," he added.-TradeArabia News Service