Rail operator expects to complete tunnelling phase by second quarter of 2017
Qatar Rail has completed nearly 20km of tunnelling out of a total of 113km for the Doha Metro project, it said at a press conference.
The transport company has already received the 21 tunnel boring machines (TBMs) assigned for the project, which were supplied by Herrenknecht, a German company specialised in mechanised tunnelling technology.
Most of the TBMs are currently operational, and Qatar Rail expects to complete the tunnelling phase by the second quarter of 2017, the company said in a statement.
“During the past year, we have achieved remarkable milestones on the Doha Metro and Lusail Light Rail Transit (LRT) projects thanks to the joint efforts of the company and its contractors,” said Eng. Saad Ahmed Al Muhannadi, chief executive of Qatar Rail.
“The tunnelling phase for the Doha Metro was successfully launched as we achieved great records of 11,880m of tunnel dug at the Red Line, 6,653m at the Green Line and 150m at the Gold Line. With a skilled team and advanced machines, we were able to tackle obstacles and ensure works are moving forward.”
The TBMs form circular tunnels through the rock and can install concrete linings along drilled sections in order to reinforce the bored tunnel and stabilise the ground.
They need only one point of entry and can drill right below the city streets without interrupting the city above, making them ideal for periods of long and uninterrupted tunnelling, as required by the Doha Metro.
The metro project is using 7-metre diameter TBMs, to produce a tunnel with a diameter of 6.7m. Among three major types of TBMs – Earth Pressure Balance (EPB), Slurry Shield and Open Face – EPB machines were selected for the Doha Metro due to the nature of the country’s geological makeup. These machines are best suited for use in cohesive soft ground and rock conditions.
Commenting on the difficulties that can arise from tunnelling underground, Al Muhannadi said that complications can be of two kinds, logistical and geotechnical.
“Technical hitches cannot be avoided while implementing such a huge and complex project. However, they can be dealt with in an efficient, effective and timely manner,” he explained. “We were proud of the team who handled a flooding situation at Al Bidda station earlier this year, which had no delay or impact on the Doha Metro progress. When and if such incidents occur, it is our duty to react immediately.”