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SBU-M Spec Sheet
The Motorized SBU is the optimal choice for longer utility installations (over 300 ft) or for crossings with specific line and grade requirements. The SBU-M is an intermittently manned, articulated mixed ground and hard rock boring machine for use with standard Auger Boring Machines (ABMs) or pipe jacking systems.
SBU-DS Spec Sheet
The small diameter Double Shield TBM (SBU-DS) is ideal for long tunnels (up to 3 km) without intermediate access. The SBU-DS, in diameters from 2.2 to 3.0 m (88 to 118 inches) is a manned-entry, hard rock tunnel boring machine.
SBU-A Spec Sheet
The Small Boring Unit (SBU-A) is a proven solution for medium to hard rock utility installations up to 150 m in length. The SBU-A can be used with any conventional auger boring machine (ABM) from 0.6 to 1.8 m in diameter and utilizes a full-face auger for spoils removal. Before excavation, the SBU-A is welded to the lead casing. A full-face auger is added to the casing and the assembly is lowered onto the ABM track. In hard rock, the circular cutterhead is tted with disc cutters, while in mixed ground a combination of ripper teeth, drag, bits, and disc cutters are used.
Robbins Product Brochure
From tunnel boring machines to cutting tools and continuous conveyors, Robbins is a total supply company. Read the brochure to find out about our latest products, world-class services and unparalleled support.
Complimentary Webinar: Know What's Ahead of You
Your project has to keep moving forward, whether the challenge is high cover, squeezing ground, fault zones, or water inflows. New ground investigation and treatment options can give you the tools to conquer what you face while maximizing TBM performance and safety.
In this complimentary 60-minute webinar, Robbins Chief Engineer Dennis Ofiara will discuss Difficult Ground Solutions (DGS)–a suite of options available for shielded hard rock and Crossover TBMs that can keep your machine moving in long tunnels, high cover, and challenging geological features. DGS is about visualization: A machine shield doesn’t have to obstruct your view of the ground around you. With a host of features like 360-degree, long distance probe drilling, convergence measuring sensors that alert operators to squeezing ground, and canopy drills for ground consolidation, you can stay a stroke ahead of your TBM operation.
We invite you to submit your questions beforehand to webinars@robbinstbm.com to get a thoughtful and well-researched answer from Dennis during the Q&A session at the end of the webinar.
Day: November 2, 2016
Time: 7 AM PDT/10 AM EDT/2 PM GMT
Click to View Recording of Webinar
Robbins Single Shield to repair a Part of World’s Longest Tunnel
Robbins has completed the manufacture and testing of a unique tunnel boring machine that will be used to repair the longest continuous tunnel in the world. The TBM will be used to overhaul a section of New York City’s Delaware Aqueduct, a 137 km (85 mi) long tunnel that delivers about 50 percent of the City’s drinking water each day. Over the span of two days in February, representatives from the owner New York Department of Environmental Protection (NYDEP), consultant McMillen Jacobs (MJ), and JV contractor Kiewit-Shea Constructors (KSC) traveled to the Robbins facility in Solon, Ohio to witness the Factory Acceptance Testing of the custom tunnel boring machine.
The Robbins Single Shield TBM will bore a tunnel to replace a 3.8 km (2.4 mi) stretch of the Delaware Aqueduct. The Delaware Aqueduct currently leaks about 75 million liters (20 million gallons) of water per day into the Hudson River. Investigations of the Delaware Aqueduct dating back more than a decade revealed cracks in the tunnel lining. While several inspections with an automated underwater vehicle showed that these cracks were stable, it was determined they could not be fixed from within the existing tunnel. New York City then decided that a new tunnel would be built under the river to bypass the leakage.
To build a bypass tunnel around the aqueduct’s leaking section, Robbins manufactured the 6.8 m (21.6 ft) diameter Single Shield TBM to safely seal against pressures up to 30 bar, and to operate in variable hard rock conditions. The Delaware Aqueduct was completed in 1944. During its original construction, work crews documented groundwater inflows of 7.5 to 15 million liters (2 to 4 million gallons) per day. Because this particular section of the tunnel lies 183 m (600 ft) below the Hudson River, the inflows are under immense head pressure and thus require the unique tunneling technology.
Due to the challenges presented by the Aqueduct Repair, such as difficult geology and considerable water inflows, the TBM had to be designed accordingly. Difficult Ground Solutions (DGS) features, including powerful drilling, grouting, and water inflow control systems have been incorporated into the machine’s design to overcome the expected challenges. “One unique feature of this TBM is the closeable bulkhead, which allows the excavation chamber to be sealed off,” said KSC Tunnel Manager Niels Kofoed. “We expect this to be a key feature in the event that groundwater flows (shunt flows) from the excavated portion of the tunnel cause washout of the annulus grout. Once the bulkhead is closed the groundwater flows are stopped and secondary grouting of the precast liner can be performed, effectively cutting off the flow path of the shunt flows.”
Robbins Project Manager Martino Scialpi further noted that, “the TBM was designed with a 9,500 liter/min (2,500 gallon/min) dewatering capacity. The machine is equipped with two drills in the shields for drilling through the head in 16 different positions and a third drill on the erector to drill through the shields in an additional 14 positions. Drilling and pre-excavation grouting will be a routine job to control and minimize water inflows.” In addition, water-powered, high pressure down-the-hole-hammers will allow for drilling 60 to 100 m (200 to 330 ft) ahead of the machine at pressures up to 20 bar if necessary.
In order to provide access to launch and retrieve tunneling equipment, two deep shafts were constructed in the towns of Newburgh and Wappinger, New York, where the bypass will begin and end. The
project site itself poses challenges to the assembly and launch of the TBM because of the limited space available.
Robbins worked closely with KSC to ensure that TBM components were designed and sized so all could be lifted with the contractor’s hoist system and fit down the narrow, 270 m (885 ft) deep shaft. Once assembled, the machine is expected to begin boring in autumn 2017.
Robbins Double Shield digs the Andes
Chile’s Los Condores HEPP is a high cover, hard rock challenge, with 500 m (1,640 ft) of rock above the tunnel and a high-altitude jobsite 2,500 m (8,200 ft) above sea level. As of January 2017, a 4.56 m (15.0 ft) Robbins Double Shield TBM had completed boring its 900 m (2,950 ft) long access tunnel and was well on the way to boring the first section of headrace tunnel. The machine embarked on its journey on May 27, 2016, and has since excavated over 1,300 m (4,270 ft) of tunnel in total.
The journey to machine launch was an arduous one, requiring shipment of TBM components and vehicle transport on unpaved, mountainous roads. Contractor Ferrovial Agroman is responsible for the intake tunnel at the Los Condores Hydroelectric Project, and was well aware of the challenges associated with machine launch: “The location of the work is a big constraint due to its rugged terrain and geographical location in the Andes. With all this, we are anxious to perform work in an efficient manner,” said Pello Idigoras, Tunnel Production Manager for Ferrovial Agroman.
The jobsite, located 360 km (224 mi) south of Santiago, Chile, is part of a new 150 MW power plant and intake tunnel. The Robbins Double Shield TBM is boring two sections of the intake tunnel, the first measuring 6 km (3.7 mi) and the second measuring 4.4 km (2.7 mi). A section between the two tunnels will be excavated by drill and blast to connect them, making the intake tunnel about 12 km (7.5 mi) in length. “This project brings an increase in energy production in the country, thus contributing to the overall improvement in the welfare of its citizens,” said Idigoras of the effect the completed hydropower project will have on surrounding areas.
The tunnel, located in the mountainous Maule Region of Chile, is being bored in two types of rock: sedimentary and volcanic. The rock has been tested at strengths up to 100 MPa (14,500 psi) UCS, with at least two fault zones””the first of which has already been traversed in rhyolite, andesite, tuff, and breccia. For Idigoras, the conditions are well-suited to Double Shield tunneling: “We have good quality medium to hard rock for Double Shield excavation overall,” he said. Despite that, some areas of challenging ground persist. To cope with the conditions, including steadily increasing water inflows at rates of up to 3,500 l/min (925 gal/min), the contractor is utilizing cementitious grouting and chemical grouting with polyurethane and foam. Such ground conditioning techniques were anticipated and the Robbins Double shield was designed to effectively apply these techniques.
As the TBM excavates, it is lining the tunnel with 250 mm (10 in) thick, 1.2 m (3.9 ft) long concrete segments in a 4+1 arrangement. The machine is currently progressing at a rate of up to 25 rings per 20 hours of boring. Crews are operating in two 10-hour shifts with one 4-hour shift dedicated to maintenance. Idigoras sees the TBM performance and completion of the access tunnel as huge project milestones, though much work remains to be done. “After many months working in engineering, manufacturing, installation, and commissioning, we are proud to see this result. It would be impossible to name all the people who participated in this project thus far but they, as a whole, have managed to get the TBM started digging and boring well.”
Carving a Path Through Extreme Conditions: An Integrated Ground Investigation System Optimized For Turkey's Difficult Geology
Turkey’s geologic framework, seated on an active tectonic belt, is made up of older rocks mixed with younger igneous rock. More than 80% of the country’s surface is rough and mountainous, and the ground conditions can be highly variable and unpredictable. Today’s adaptable TBMs are capable of tackling these tough conditions using cutting-edge technology coupled with modern ground investigation methods.
This presentation will explore several recent and ongoing projects in the tunneling industry that highlight the latest in TBM technology for difficult ground excavation. Whether smart features include a Measurement While Drilling (MWD) system, cutterhead inspection cameras, or sensors to monitor converging ground, today’s TBMs equip contractors with knowledge. Specialized sealing systems can arm contractors with methods to successfully and safely treat water head pressure up to 30 bar.
Robbins TBM dubbed "Driller Mike" digs Atlanta
After an Onsite First Time Assembly (OFTA) lasting just 2.5 months, Atlanta Georgia, USA’s newest TBM, dubbed “Driller Mike”, made its initial startup on October 13, 2016 and ramped up to full production two weeks later. Atlanta’s Mayor Kasim Reed and city officials gathered with local and national media to celebrate the occasion. The 3.8 m (12.5 ft) diameter Robbins Main Beam TBM is now boring the 8.0 km (5.0 mi) Bellwood Tunnel after being walked forward 100 ft into a starter tunnel. The Bellwood Tunnel path will travel from an inactive quarry and run below a water treatment plant and reservoir before ending next to the Chattahoochee River.
The project was green-lighted by the City of Atlanta’s Department of Watershed Management due to the city’s current emergency water supply shortage. The PC/Russell JV, the project’s construction manager at risk, sub-contracted with the Atkinson/Technique JV to operate the TBM and will oversee construction of various intake and pumping shafts as well as final lining operations. The project is of utmost importance for the City of Atlanta, explained Bob Huie, Sr. Project Manager for the PC/Russell JV. “Right now, the downtown area’s emergency water supply is approximately three days. With the tunnel the supply will increase to between 30 and 90 days. To be a part of the city’s emergency water supply solution is huge. This tunnel will protect the city for a very long time.”
With the tunnel on the fast track, swift TBM assembly was key. The OFTA process involved coordination by multiple crews at the large quarry site. “The OFTA went very well. The overall assembly process was well organized and supervised by the Atkinson/Technique JV and Robbins. We had a good team of folks to put it all together,” said Huie. He continued: “This is a unique job where there’s a lot of people with a variety of backgrounds, but everyone came together to make the OFTA happen.”
The Robbins TBM is now excavating in granite, with at least 300 m (1,000 ft) of zones in three separate areas that will require continuous probing. In a section directly below an existing reservoir, monitoring will be particularly crucial to ensure no water inflows occur. The Robbins machine will also be required to negotiate several curves: “We have one curve in the first 300 m (1,000 ft) and the main 370 m (1,200 ft) radius curve is 1,800 m (6,000 ft) in. We plan to do short TBM strokes in this section™bout 20 cm (8 inches) to 30 cm (1 ft) shorter than normal to get through the curves,” said Larry Weslowski, Tunneling Superintendent for the PC/Russell JV.
Excavation is scheduled to be completed in the first quarter of 2018. After final lining, the tunnel will be filled with water and the quarry site will become Atlanta’s largest reservoir and park, totaling hundreds of acres. While the park site is a bonus for residents, the water storage capacity it will provide is critical. Nearly 1.2 million customers, including 200,000 passengers who pass through the world’s busiest airport every day, count on the water supply each time they turn on the tap. “If the city were to lose water supply for a day, the estimated economic impact would be at least USD $100 million per day. If you consider that this is a USD $300 million project, that seems a pretty good investment in comparison to what could happen,” said Huie.
Bangalore Fanfare Marks Final Breakthrough for Robbins EPB
On September 23, 2016, Bangalore’s last TBM for the city’s metro rail project broke through, marking the end of TBM tunneling on the Namma Metro phase 1. The Robbins-operated machine, known as “Krishna”, bored a 750 m (2,460 ft) drive through challenging conditions between Chickpet and Majestic stations. Cleanup and final commissioning of the tunnel will be completed in 2017, and is the last obstacle before owner Bangalore Metro Rail Corporation Ltd. (BMRCL) can open the Malleswaram-Majestic link. The TBM’s sister machine, “Kaveri”, completed a parallel tunnel in June 2016.
The success follows a gauntlet of challenges on the two tunnel sites. Due to severe delays on the original tunnel drives, Robbins was approached and asked to take over the operations of the remaining two competitor-manufactured TBMs in February 2015. After obtaining agreement from the project owner and the contractor, Robbins took over the responsibility for all aspects of the underground operations. “We provided a team of over 60 staff including TBM operators, TBM technicians, ring builders, a grouting team, and more. We were also responsible for running surface installations and equipment such as the grout batching plant, gantry cranes and power supply. Contractor Coastal Projects Ltd. (CPL) provided a team of people including surveyors, QC engineers, and loco operators who reported directly to our site management team,” explained Jim Clark, Projects Manager for Robbins India.
The Robbins crew carried out tunneling operations while the Chickpet station was being constructed around them to mitigate delays incurred before they took over project operations. The project’s most difficult challenges included a low overburden and unconsolidated ground along the alignment, and the discovery of several uncharted wells directly on the alignment. Difficult ground frequently prevented proper pressurization during cutting tool replacement, requiring a grout solution to be pumped in to fill voids and left to cure. Initially the curing process took up to 36 hours, but with improved application methods this was reduced to a 12-hour curing time.
Another challenge involved the sensitive building structures along the tunnel path. Issues with surface vibration, explained Clark, required that cutterhead speed be limited to 1.8 RPM during the day shift and 1.2 RPM during the night shift. Despite the obstacles, the TBMs advanced at rates of up to 50mm (2 in)/min in highly weathered rock.
“This is an industry first, wherein a TBM manufacturer has utilized their in-house expertise and knowledge to take on this level of responsibility for a project,” said Clark, addressing the magnitude of the successful breakthroughs. “The fact that it was “˜a first’ and we were successful in bringing this high-profile project back on track is a great achievement for The Robbins Company.”
Now that tunneling is complete, the North and South runs of the Namma metro will be connected–a line that, once in service, will carry an estimated 40,000 passengers daily. It is anticipated that Phase One of the metro will be opened in its entirety in 2017.