Brokk robots assist in Doha Metro project

Published 16/5, 2017 at 15:54

A team of 10 remotely controlled Brokk Robots is playing a key role in the massive $17.8bn (€16.7bn) Doha Metro railway project in Qatar. The Brokk 160s and Brokk 260s, equipped with a variety of attachments, are working in pairs excavating the cross passages between the two main running tunnels.

The Doha Metro for Qatar Rail will eventually consist of four lines, Red, Green, Gold and Blue and opening in phases beginning in 2019 with an eventual completion date of 2026. The Red, Green and Gold lines will radiate out from a central interchange at Msheireb in Downtown Doha, with the Blue line providing a semi-orbital service.  A team of 21 tunnel boring machines is driving the main tunnels on this multi joint venture project that will have a total length of 211.9km and encompass 85 stations when complete.

The Brokk machines have been working on the Red and Gold lines. The southern part of the Red line consists of two 30km parallel tunnels with 34 cross passages and six sub-pits in the tunnel inverts for collecting and pumping out water.  The cross passages are 5m in diameter and a variety of lengths ranging from 10m to 40m.

The Brokk machines have been used as the primary method of excavating the cross passages. The contractor chose a Brokk 260 and a Brokk 160 with a variety of attachments, such as bucket, breaker, rock drill and scabbler, to accomplish a multitude of tasks. In order to speed up production, a machine was placed at either end of the cross passage with the goal of meeting in the middle. Progress has averaged about 25m3/day, with a relatively soft rock hardness of around 10-20MPA.

The Brokk machines have also been used to trim the edges of the profile. “This is the first time I have been working with Brokk machines. I am really impressed with their flexibility. They are good powerful machines to work in confined space,” said Red Line South cross passage manager Nicolas Combe.

The Gold line, which used six Brokk B160s, consists of two 30km tunnels with 20 stations and 23 cross passages and seven sub-pits to pump out water. Four of the Brokks have been equipped with TEI drilling rigs, breakers, scabblers and shotcrete attachments. The Brokks started with a TEI-drill making about 40 holes of 75mm diameter to a depth of 9m to secure the cross passage.  The hardness in the rock was up to 120MPA. Afterwards a breaker attachment has been used for excavating through the rock or, in softer areas, a Brokk scabbler attachment. The Brokk machines were also used to trim the edges. A shotcrete attachment was used to secure the cross passages and also a bucket to remove the debris.

“The advantages of using Brokk machines are their capacity to operate in confined spaces, their ability to handle a variety of different applications and of course their remote control safety features. A perfect machine for demanding tasks such as producing cross-passages,” said Gold Line plant manager John Broumis.

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