TBMs accepted for the Dubai stormwater drives 23 Aug 2018

Two 11.05m diameter TBMs have been accepted at the Guangzhou factory of CREG in China ready for shipping to the stormwater management project in Dubai. Procured by the design-build construction joint venture of Porr, Austria and Six Construct, part of the Besix Group of Belgium, the two machines were ordered in November 2017 and have been designed and built within nine months, to meet the tight procurement schedule and factory acceptance testing schedule in July 2018. Both machines are now being disassembled ready for shipment to Dubai in October and planned launch of both before the end of 2018.

Acceptance of the two EPBMs at the CREG factory in Guangzhou

The Porr-Six Construct JV was awarded the AED1.3 billion (US$354 million) design-build stormwater tunnel contract by project owner Dubai Municipality in early October 2017. With negotiations in place with CREG, it confirmed the order for the two EPBMs in November. Speaking at the factory acceptance ceremony, Christoph Duempelmann of Porr and Project Director for the JV joined Francois Springuel of Six Construct, Deputy Project Director, and Zhang Zhiguo, Group Director and Deputy General Manager of CREG, to sign the acceptance certificate. The factory tests were attended also by senior representatives of Dubai Municipality and the Project Management Consultant MWH (now part of the Stantec Group), and under the leadership of Dr Jayapregasham Tharamapalan.

Project Director Tharamapalan for Dubai Municipality said that the early procurement of the TBMs and their timely manufacture by CREG to met the strict factory acceptance tests formed an important milestone in the project. He added that Dubai Municipality was pleased that the two brand new machines were purpose-built in such a short duration to meet the extremely tight project schedule.

TBMs will complete 10km of stormwater conveyance

“The Porr-Six Construct JV and CREG have worked hard to meet the tight schedule,” confirmed Project Director Duempelmann at the ceremony. “To finalize negotiations for such long-lead key equipment, and then design and manufacture two completely new TBMs of this scale in only nine months is extremely challenging, and was only achieved due to the commitment of all parties - the joint venture, including the Porr technical head office team; the TBM manufacturer; the project designer, the project management consultant and Dubai Municipality”. Duempelmann confirmed the works are on track for completion of the project before the target date, which is for when Dubai hosts the World Expo opening in October 2020.

“The track record of CREG introducing EPB TBMs for the tunneling market is very impressive and this, along with the number of TBMs produced, convinced us to order the two TBMs for this project with CREG,” said Deputy Project Director Springuel.

The two machines will excavate about 5km each and in in three drives to complete the 10km x 10m i.d. segmentally lined tunnel at up to 45m deep. One of the machines will progress from a central working shaft and excavate about 2.5km in each direction, being disassembled at the end of its first drive and returning for relaunch from the working shaft for the second opposite direction drive. As the machines advance, muck will be hauled to the surface via continuous conveyor systems supplied by Marti Technik of Switzerland and the lining segments will be delivered using MSVs (multi-service vehicles) supplied by Metalliance of France. Technical teams from CREG will be on site to assist with the assembly of the two machines. In the meantime on site in Dubai, Swissboring is installing the 1.2m thick diaphragm walls for the excavation of the five shafts of up to 22m diameter and 52m deep required for the contract.

Christoph Duempelmann, JV Project Director (right) and Francois Springuel, Deputy Project Director (left) joined Zhang Zhiguo, Group Director, Deputy General Manager of CREG at the factory testing and acceptance ceremony

The objective of the stromwater drainage project is to collect and manage groundwater and stormwater runoff from the city’s World Central area and adjacent communities. At a combined area of about 380km², this represents about 40% of the Dubai urban area and encompasses the new Dubai South development area that includes the city’s new Al Maktoum International Airport, the Expo 2020 site and several other emerging developments. The infrastructure is built to serve also planned and future growth of residential and business communities in Dubai. Although rare, the Gulf States regions experience extreme storm rainfall events, the impact of which, in the urbanised area of Dubai, in conjunction with a high natural ground water level, causes severe flooding.

The main large diameter tunnel is one of three main contracts for the overall project that is designed to control both rainwater and groundwater (Fig 1). The overall AED12.5 billion (US$3.4 billion) project has another four elements:

• A further 10km of large diameter gravity flow lateral conveyance tunnel
• A network of up to 125km of gravity flow 1m to 3m diameter stormwater pipelines
• A 95 hectare detention pond
• A high efficiency 30m³/sec capacity pumping station; and
• A sea outfall comprised of three x 500m long x 2m diameter pipelines.  

MWH Global, now Stantec, has been working on the project as consulting engineer for the Dubai Municipality since wining the commission against strong competition in December 2015. The project is designed to give a service for the city of Dubai for the coming 60 to 100 years.

Design and purpose of the stormwater management project

Competition for the first of the main tunnel contracts was also strong between the contractors prequalified to bid for packages 2 and 3, which included:

• Salini Impregilo (Italy);
• Samsung C&T (South Korea) / Ghella (Italy);
• Acciona (Spain) / Larsen & Toubro (India);
• Vinci Construction (France),
• Bouygues (France),
• Porr (Austria) / Besix (Belgium),
• Hyundai Engineering & Construction (South Korea),
• Strabag (Austria) / Gulermak (Turkey).

Those prequalified for construction of the pumping station include:

• Besix (Belgium),
• Odebrecht (Brazil),
• Vinci Construction (France),
• Archirodon (Greece), and
• The Larsen & Toubro (India) / Samsung Engineering (South Korea) JV.

The hosting of the World Expo in Dubai in 2020 is supporting a surge in infrastructure investment in Dubai. It is reported that, to date, an estimated US$2-4 billion has been invested on developing the Dubai Expo 2020 site and further infrastructure projects are included in the budgeted US$8 billion Dubai 2020 Urban Master Plan. These include the US$2.9 billion Metro Red Line extension to the Expo 2020 site and on to the Al Maktoum International Airport, the US$2 billion Phase 2 expansion of the Al Maktoum Airport in time for the Expo 2020 event, and another US$390 million to be invested in planned road works.

Earlier plans for part of the large diameter stormwater tunnels to be designed as a dual mode facility with a road deck built into the internal space and closed to traffic in times of heavy rainfall when full capacity of the stormwater facility is needed have been dismissed. The concept was first developed and built for the dual stormwater plus road SMART tunnel in Kuala Lumpur, Malaysia.