Robbins unveils Largest Hard Rock TBM in the U.S. at Mill Creek
Jan 24, 2020
In December 2019, the City of Dallas, Texas, USA unveiled the largest hard rock TBM ever to bore in the U.S. The 11.6 m (38.1 ft) diameter Robbins Main Beam TBM will excavate the 8 km (5 mi) Mill Creek Drainage Relief tunnel, and its size is not its only distinction. The adaptable machine will change size partway through the bore, to a more compact 9.9 m (32.5 ft).
The unique Robbins TBM will be used to dig a tunnel designed to provide 100-year flood protection for east and southeast Dallas, areas affected in recent years by severe storms. The tunnel will protect 2,200 commercial and residential properties, including Baylor Medical Center.
The current drainage system in these areas was constructed 50 to 70 years ago, and only provides two to five years of flood protection. “The completion of the TBM assembly marks a major milestone in the Mill Creek Tunnel Project,” said Council Member Lee Kleinman, chair of the Transportation and Infrastructure Committee for the City of Dallas. “I’m thrilled to see this type of engineering marvel happening right here in Dallas.”
The dual-diameter aspect of the Robbins TBM will be a first-of-its-kind conversion process. The contractor, Southland/Mole Joint Venture (SMJV), will make the conversion underground about 2.8 km (1.8 mi) into the bore.
The two diameters are needed as the upstream section of the tunnel is designed with a circular cross section and peak flow rate of 42 m3/sec (15,000 ft3/sec), while the downstream 2.8 km (1.8 mi) portion has a higher peak flow of 565 m3/sec (20,000 ft3/sec) and was initially designed as a horseshoe cross section. Using the TBM for the entire tunnel is less time consuming and costly.
“Robbins and SMJV are working closely to create the safest and most efficient sequence for completing this conversion within the limits of the bore. The City of Dallas (Owner) and our Project Team are very excited to embark on this unique challenge,” said Nick Jencopale, Project Manager for Southland Holdings.
The Robbins TBM, named “Big Tex” with permission of the State Fair of Texas, has been designed with a specialized cutterhead including removable spacers and adjustable bucket lips to convert to a smaller diameter. The TBM will first complete its 11.6 m (38.1 ft) diameter section of the alignment, then back up about 21 m (75 ft) to a transition area for the conversion, which is expected to take six to eight weeks.
As the TBM bores, it will pass through Austin Chalk between 12 to 30 MPa (1,800 to 4,400 at depths from 31 to 46 m (100 to 150 ft) below the city. The route is potentially gassy, so probe drilling is mandatory throughout the project. Crews will utilize ground support including eight 3.9 m (13 ft) long rock bolts every 1.5m (5 ft) with wire mesh and channel straps as needed. The finished tunnel will be lined with a 380 mm (15 in) thick cast-in-place concrete lining.
“Big Tex will work 24 hours a day to excavate the tunnel with crews ranging in size depending on activities,” said Rachel Sackett, marketing and communications director for Southland Holdings. Based on previous work through similar geology, the project team expects TBM excavation to progress rapidly to an average of 25m (80 ft) per day, allowing the project to be completed on schedule in 2023.
More News and Articles
May 08, 2024
News
Improving trenchless installations with Riteline
Riteline spacers have been successfully appraised by the Water Services Association of Australia, providing a new option for pipeline installations that complies with WSA PS-324 for casing spacers.
May 06, 2024
News
Redefining relining in Wodonga
In a step towards enhancing stormwater infrastructure, M. Tucker & Sons recently completed a challenging relining project for the Wodonga City Council.
The relining project, commissioned by the Wodonga City Council …
Apr 29, 2024
News
Minimising cultural impacts with trenchless
Through the benefits of trenchless technology, Yarra Valley Water is minimising impacts on the Upper Darebin Creek branch sewer project.
The project consists of building a 2.7km sewer pipe in Epping, …
Apr 26, 2024
News
Bothar’s cutting head innovation
The trenchless industry in Australia continues to grow and the need to provide customised solutions becomes vital for a leading subsurface contractor.
Recognising the need for advanced solutions to meet the growing …
Apr 24, 2024
News
Sustainable drainage solutions: German Start-up transforms urban water management.
Germany boasts a well-established infrastructure for managing rainwater and wastewater, yet many developing countries lack such systems. Addressing this gap, …
Apr 22, 2024
News
HDD tooling that gets the job done
Horizontal directional drilling is a dynamic process that constantly changes and adapts to suit a range of applications across utilities and infrastructure. Operators looking to get the most from their equipment …
Apr 19, 2024
News
WATCH: Overnight with SAERTEX-LINER H20 in São Paulo
Available through Pipe Core, high-quality liner SAERTEX-LINER H20 performed under pressure in São Paulo, Brazil.
Maintaining aging potable water pipe infrastructure is a constant challenge …
Apr 17, 2024
News
Immersive media provides wastewater experience in Denmark
An immersive media experience (IMX) may not be what most people want when they think about industrial wastewater, but that is exactly what visitors can expect when they visit a new installation …
Apr 15, 2024
News
Spotlight on gender diversity at Pipe Core
Since founding in 2008, Pipe Core’s team has grown across all areas of the business and is now in a position where there are more females than males across the organisation. Research published in Harvard …
Apr 12, 2024
News
New Wave of Startups Scale Innovation to Solve Global Water Challenges
Innovators from Around the World Join Xylem’s 2024 Accelerator Program to Deploy Breakthrough Innovations for Utilities and Industrial Users of Water
A new group of startups …
Apr 08, 2024
News
Integrated sustainable electricity and clean drinking water systems
Altitude Water and New Use Energy Solutions have partnered to create integrated, mobile solar-plus-water generation systems that produce sustainable electricity and clean drinking …
Apr 05, 2024
News
How to Evaluate Hydraulic Fracture Risk in HDD Design
The design of horizontal directional drill (HDD) installations often requires an evaluation of the potential for hydraulic fracture of the soil layers through which an HDD passes. Evaluating …
Contact
The Robbins Company
Desiree Willis
Technical Writer
29100 Hall Street
OH 44139 Solon
United States
Phone:
+1 253.872.4490