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The Robbins Company Announces Joe Lechner to SBU Sales
The Robbins Company announced the appointment of Joe Lechner to the role of Small Boring Unit (SBU) Sales Manager. With over 18 years of industry experience, the role is a natural career progression for Lechner. It brings him back to his early roots of working with SBUs, while more recently he worked with TBMs. Lechner can continue his success with the company in this new capacity with the trenchless division.
In his new position, Lechner will handle SBU sales and rentals for Robbins, assist customers in equipment specifications for projects, and provide full-spectrum customer support. In addition, Lechner will be responsible for many other tasks such as generating quotes for cutters and spare parts, shop scheduling, forecasting, internal operations for Robbins, and field service support, as needed.
“I want customers to know they can come to me with any issues. I have a good understanding of the industry and our business,” said Lechner. “I want to provide an all-around good experience. Robbins wants your project to be successful, with our equipment and support.”
Lechner began working with SBUs in 1998, starting in field service. When he wasn’t out in the field, he was building SBUs and cutters. He started up and commissioned SBU-As in the field, and transitioned over to working with TBMs worldwide in the mid 2000’s. With his diverse worldwide field experience, Lechner’s knowledge will continue to benefit Robbins and its customers.
Lechner said his goals as Sales Manager for the SBU product line for the next two years include increasing stocking levels and providing fast deliveries to customers. He noted the division is streamlining inspection quoting and repair processes to ultimately provide the most efficient services possible. With a few hundred machines in service, some of which are working around the clock, he anticipates product sales, rentals and repairs all will remain consistent moving forward.
“We’re lucky to have Joe working with Robbins,” said Tom Fuerst, Utility Tunneling Sales Manager. “With his background and extensive knowledge, he’ll easily implement the best solutions for our customers.”
Robbins Achieves another Breakthrough in Bangalore
In February 2015, Robbins, with its operating company Robbins India, was asked by Bangalore Metro Rail Corporation Limited to take over the operation and maintenance of two competitor-owned EPBMs. The machines were stalled due to low performance and financial issues from the Operating Contractor and lack of support by the original machine supplier. As the North-South Bangalore Phase 1 Metro tunnels were on the critical path, the BMRC looked to Robbins to step in and take over the troubled project. A Robbins/Robbins India team of 70 field service personnel refurbished and modified the existing equipment, both while in the tunnel and before relaunching the machines in Chickpet station. In addition, the on-site Robbins/Robbins India Team supervised all aspects of TBM excavation, segmental lining, mucking and grout plant operations since the relaunch of the machines for both drives.
“I am particularly proud of being involved in this project, and to support BMRC with the completion of this tunnel drive and bringing the project back on schedule. This is also the first time The Robbins Company has been responsible for the complete scope of operations on a project,” noted Jim Clark, Projects Manager with Robbins India. “One of the biggest challenges we faced was carrying out cutterhead interventions under compressed air in mixed ground conditions that consisted of varying grades of granite in the lower half of the face, and loose, unconsolidated material in the upper section of the face.”
Clark said that on numerous occasions, compressed air would percolate through to the surface, forcing crews to abort cutterhead interventions. They eventually found a solution by pumping a weak mix grout though the mixing chamber, and into the geology surrounding the tunnel face. The weak mix grout stabilized the ground sufficiently so the cutterhead interventions could be completed.
The Robbins crew carried out tunneling operations while the 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 consolidated ground along the alignment, and the discovery of several uncharted wells directly on the alignment. In addition, the majority of the tunnel was bored directly beneath buildings constructed upon what is today considered substandard foundations.
This portion of the Phase One Metro tunnels runs from Chickpet to Majestic at Namma Metro. Once Krishna breaks through, the North and South runs of Bengaluru will be connected, allowing service to an average of 40,000 passengers daily. It is being completed under a tripartite agreement between Robbins India, Coastal Projects Limited, the lead contractor, and project owner, Bangalore Metro Rail Corporation Limited. It is anticipated Phase One will be open in its entirety by November, 2016.
A Novel Continuous Conveyor System and its Role in Record-Setting Rates at the Indianapolis Deep Rock Tunnel Connector
The Indianapolis Deep Rock Tunnel Connector (DRTC)—first in a vast network of storm water storage tunnels below Indiana, USA—was a wildly successful endeavor. Crews for the Shea/Kiewit JV drove a 6.2 m Robbins Main Beam TBM to world record rates. The machine achieved 124.9 m/day, 515.1 m/week, and 1,754 m/month in limestone and dolomite rock. The advance rates can be attributed to many factors including ground conditions and knowledgeable crew, but continuous conveyors are also of key importance.
The novel conveyor system, manufactured by The Robbins Company, enabled continuous tunneling in a difficult layout that included two 90-degree curves and two S-curves. Spanning 11,777 m in its longest iteration, the system included nine booster drives plus a main drive. A vertical belt moved muck up the 76 m deep shaft to a radial stacker for temporary storage. The system, one of the most complex in North America and the first to operate in 90-degree curves, made swift tunneling possible.
This paper will examine the world-class tunneling done at the Indianapolis DRTC and the role of continuous conveyance in reaching high advance rates. The logistics of the system will also be examined as it could apply to future tunneling projects with similarly complex layouts.
Use of Two Novel Hybrid-Type “Crossover” TBMs for Hard Rock Conditions with Water Inflows
Mixed ground tunnels come in all kinds. In rock tunnels with possible faults and high pressure water, the challenges are many. With the advent of Crossover TBMs, contractors can minimize risk in such conditions while maximizing efficiency. The newest generation of Crossover is exemplified by two projects in Albania and Turkey.
A 5.56 m Crossover TBM destined for Turkey’s Gerede Water Transmission will be assembled using Onsite First Time Assembly (OFTA) from within an existing tunnel. The unique machine will bore through 30 fault zones requiring the TBM to be sealable to up to 20 bar so pre-consolidation grouting can be done. EPB mode will only be used in poor ground—in this mode, the TBM will bore sequentially using the screw conveyor fore and aft gates.
Skewing further towards hard rock, a unique 6.2 m diameter Double Shield TBM with Crossover features was designed for Albania’s Moglicë Headrace Tunnel. The machine features closure doors and a sealing system to contain inrushes of water until they can be grouted off.
This paper will discuss the unique aspects of the Crossover designs and their utilization at the two projects.
The Next Generation of TBMs for Mining Applications
TBMs have been used in mining in decades past, but their use has been limited and sporadic, due to both perceived and actual application difficulties. With new technology and mounting success stories, this is changing. For both coal and metallurgical mining, deep ore bodies require long access tunnels, and an efficient and economical method of reaching those deposits.
Today, mining engineers are considering TBMs as part of the overall mine development plan. Planned TBM mine drifts are not only longer, but have more complicated trajectories. Mine development TBMs will have to cope with varying geology, potential for high water inflows, steep gradients, and high temperatures. TBM systems are being planned to cope with such difficulties. TBM systems will be considered and increasingly deployed for mine development, even if commodity prices remain low. TBMs can satisfy the need for increased productivity, better life of mine infrastructure, and safety.
This paper will review the historical use of TBMs in mining, and will discuss the 2015 status of TBMs in mining, and the special requirements and adaptable features needed in order to make efficient TBMs a reality in mines worldwide.
Concurrent Segment Lining and TBM Design: A Coordinated Approach for Tunneling Success
The success of a tunnel project relies on many factors, but one of the most important is also the most overlooked: coordination by all parties involved during the design stages. This is particularly true of segment design and TBM design. Tunnel lining with segmental rings is usually designed according to the standards of reinforced concrete construction based on a given GBR. However, for TBM tunneling, the determination of loads during ring erection, advance of the TBM, earth pressure, and bedding of the articulated ring are all part of the tunnel lining design as well. TBM design can be heavily affected by the segment arrangement, dimension, and weight, but these are usually given as a fixed input to the TBM manufacturer—a process that can cause unnecessary complications.
The authors propose that the industry evaluate the process as it stands. In order to find the optimum balance between lining design and TBM cost and operational workflow, both designs should be finalized concurrently. This requires coordination between the TBM manufacturer and segment designer from the early stages. The aim of this paper is to evaluate the influence of the segment lining design on TBM cost and performance, and to provide commentary on existing design guidelines to optimize lining and TBM procurement.
Mexico's Crossover TBM makes its Mark for Robbins
On March 29, 2016, North America’s first Crossover TBM broke new ground in Mexico City. The 8.7 m (28.5 ft) diameter Robbins XRE™ –a cross between a rock TBM and an EPB–emerged into an intermediate shaft at Emisor Poniente (TEP) II.
The machine is undergoing some maintenance before continuing on to bore the final 3.2 km (2.0 mi) of tunnel. The customized TBM, for a consortium of Aldesem, Proacon, and Recsa, was chosen based on a number of parameters that included challenging ground conditions below an area to the west of downtown Mexico City.
The tunnel path travels through a mountain with cover as high as 170 m (560 ft), through fault zones and in a section with cover as low as 8.0 m (26.2 ft) above the tunnel crown. Much of the tunnel consists of andesite rock with bands of tuff, and softer material in fault zones as well as an 874 m (2,870 ft) long section in soft ground at the end of the tunnel.
“The geological profile of the project comprises six different lithologies, among them hard rock such as dacite. To get the best operation in both areas required use of dual mode technology such as the Crossover TBM,” said Enrique del Castillo of contractor Aldesem. The 8.7 m (28.5 ft) diameter Robbins XRE (Cross between Rock/EPB) is a design that allows for the TBM to effectively bore in both hard rock and mixed ground.
The machine setup includes a canopy drill and positioner for enhanced ground consolidation, as well as gear reducers to adjust torque and RPM based on ground conditions. The TBM, initially launched in hard rock mode, can be operated in EPB mode later on by switching out the belt conveyor with a screw and converting the cutterhead.
The Robbins Crossover machine began its journey in August 2015, and advance rates picked up quickly. Project records were set in January 2016 after the machine achieved a best day of 42.8 m (140 ft) and a best week of 185.1 m (607 ft). By mid-March the machine had bored through the first of the contact zones, a 30 m wide section of fractured and blocky rock. While the excavation through the contact zone was slow going, progress picked up again in the more competent rock. Final breakthrough is expected in autumn 2016.
Once complete, the 5.8 km (3.6 mi) tunnel will supplement an existing and overtaxed wastewater line built in the 1970s. The deep drainage tunnel will serve to prevent recurrent flooding in Valle Dorado, and will benefit the cities of Cuautital Izcalli, Tlalnepantla, and Atizapan de Zaragoza, an area with a total population of 2.1 million inhabitants.
Robbins EPB surmounts Chennai Metro Challenges
On January 27, 2016, a Robbins mixed ground EPB broke through at Chennai Metro, finishing up a challenging second drive that saw the full gamut of difficult conditions. The 1,027 m long second drive for the machine was part of Lot UAA-01 on Line 1 of the city’s metro, consisting of two parallel 1.0 km (0.6 mi) tunnels running from the Washermanpet area towards Chennai International Airport. Contractor Afcons Infrastructure Ltd. reflected on the breakthrough: “We are really proud of our executing team, who have maintained a high standard of quality. We didn’t record any water leakage or settlement at the surface, and we have demonstrated a high standard of safety in the tunnel during construction,” said Mr. Gopal Dey, Sr. Manager for Afcons.
The 6.65 m (21.8 ft) diameter Robbins EPB was designed to excavate granite, sand, silt, and clay with boulders up to 300 mm (12 inches) in diameter. The specialized design utilized a combination of 17-inch diameter disc cutters as well as soft ground tools. Small grippers located around the circumference of the machine’s shield allowed for cutterhead stabilization in harder ground, while additionally reacting the forces needed to pull the cutterhead back from the face in difficult conditions.
The TBM was launched on its initial drive in January 2012 from a 28 m (92 ft) deep starting pit. Challenges began nearly from the outset. The TBM bored into mixed face conditions that contained varying strengths of granite, from weathered to hard granite of 150 MPa (21,700 psi) UCS. The unexpectedly hard rock caused high cutter consumption rates and slowed advance.
A crew of Robbins Field Service personnel and engineers assisted Afcons in remedying the problem. Robbins India provided a geologist who carried out face mapping for the whole of the first drive, in both hyperbaric and open mode conditions on a daily basis. The data not only assisted the crew in operating the TBM, but also provided a comprehensive geological record for the second drive. With the data gleaned from the geological investigation, Robbins was able to advise Afcons on the optimal operating parameters to get through the difficult conditions, including cutterhead RPM, thrust pressure, penetration rate, and cutterhead torque. The parameters also resulted in a reduced cutter consumption rate.
Contractor Afcons was pleased with the help they received: “The Robbins Field Service team extended very good services to us, particularly in the mixed face & full face rock when they deployed their Geologist for face mapping. This helped us to understand the strata ahead of us, and based on this the TBM advance rate and operating parameters were decided,” said Mr. V. Manivannan, Executive Vice President for Afcons.
The TBM was launched on its second tunnel in February 2015. Conditions were just as difficult as the first drive, but now the team approached it with experience: “We experienced very high water pressure in this alignment, as the water table in Chennai is just 1.5 m (5 ft) underground and the strata above the crown included silty sand, clay and weathered rock. It was very important for us to maintain the earth pressure to reduce the inflow of water, and to avoid any settlement on the surface with proper grouting,” said Dey. Despite the challenges the TBM was able to complete a section below the Koovam River without any water flowing into the tunnel. The machine achieved up to 12.6 m (41 ft) in one day and 62 m (203 ft) in one week.
The TBM broke through into a receiving shaft, utilizing a unique setup for the second time that had the machine emerging under water. “These were the first breakthroughs in India under wet conditions in the retrieval shaft, which is 30 m (98 ft) below the ground level. The retrieval shaft was filled with Bentonite slurry 10 m (33 ft) from the base slab in order to arrest water entry from outside the diaphragm wall,” explained Manivannan.
The completed sections of tunnel will now be commissioned as part of Line 1, a 32.1 km (19.9 mi) long route in total with 14.3 km (8.9 mi) underground and a total of 17 stations. The southeastern Indian city of Chennai is a rapidly growing technological and industrial center with a population of more than 8.2 million people and a high need for alternate means of transportation.
Rosemont Double Shield on a roll for Robbins
In a large November 2015 ceremony attended by the mayor of Montreal, Quebec, Canada, and representatives from local media outlets, the Rosemont Reservoir tunnel construction came to a close. The challenging project gave good cause for celebration as crew members crowded around the cutterhead of the 3.0 m (9.8 ft) diameter Double Shield TBM that had emerged into an exit shaft.
Local contractor Foraction, Inc., headed the excavation of the 4.0 km (2.5 mi) long tunnel with a TBM launch in December 2014. Roger Lepinay, Equipment Manager for Foraction, Inc., praised the Robbins disc cutter wear in both limestone and harder rock formations: “I was impressed by the cutters, it was a nice surprise. They were quite long-lasting compared to other cutters I have used on jobs in the past.”
Lepinay characterized the ground as “almost ideal”, with a few difficult sections. “Below Montreal there is mostly thinly bedded limestone, with some shale and intrusive igneous rocks, mainly dykes and sills,” explained project geologist Brigitte Gagné for company Exp Service Inc. While the limestone averaged 100-150 MPa UCS, rock in the intrusives ranged from 100-300 MPa. The dykes and sills were as small as a few centimeters wide and as large as 8 to 10 m (26 to 33 ft) wide. The contractor was able to successfully navigate these sections despite the varying rock strengths. Even with geologic challenges including some water inflows and over-break in small sections, the contractor was able to achieve advance rates of up to 38 m (125 ft) per day in two shifts of 9.5 hours each. Much of the ground was self-supporting, though the contractor installed rock bolts every 2.5 m (8.2 ft) into portions of the tunnel crown, while mesh, rock bolts, and steel sheets were used in the sections of unstable rock.
The long tunnel drive at small diameter was carefully planned to optimize logistics. The contractor utilized a muck train that could accommodate two pushes worth of excavated material. The first kilometer (0.6 mi) was ventilated from the launch shaft, while three surface-driven 800 mm (32 in) diameter surveying wells at the 1, 2, and 3 km (0.6, 1.2, and 1.9 mi) marks ventilated the rest of the tunnel as the TBM progressed.
With the breakthrough, an important phase of the Rosemont Reservoir project is complete. The reservoir itself was built in 1960 to increase water supply to the city and a geotechnical study for the tunnel was carried out in 1977. However, other major infrastructure projects soon took priority and the project was placed on hold. By 2010, the population of the city had increased dramatically and problems with the existing reservoirs put the project back on the fast track. The large reservoir that sat idle for decades will now be used to improve much of the city’s water supply.
As of mid-January the contractor is working to ready the tunnel for installation of the carrier pipe, consisting of 2.13 m (84 in) I.D. pre-stressed concrete cylinder pipe (PCCP). Crews will then grout the pipe in place. There will be several more work stages to be carried out before the Rosemont Reservoir is finally reconnected to the water main network in 2019.
Rossaga Main Beam makes Historic Breakthrough
A crowd of crew members gathered to celebrate in front of a newly emerged hard rock TBM on December 10, 2015 in northern Norway, but their celebration was about more than just a breakthrough. The 7.2 m (23.6 ft) diameter Robbins Main Beam machine had traversed incredibly hard rock, water inflows, and more to become the first TBM in the country to break through in over 20 years.
The 7.4 km (4.6 mi) long headrace tunnel for the RøssÃ¥ga Hydroelectric Project offered up a number of challenges to the crew. “We bored through hard, quartz-rich rock with rock strengths up to 300 MPa (43,500 psi) UCS and softer karstic limestone with water ingress,” explained Tobias Andersson, TBM Manager for contractor Leonhard Nilsen & Sønner (LNS). Despite the geological challenges, the TBM performed very well and achieved a record production of 250 m (820 ft) advance in one week, as well as a high of 54 m (177 ft) in one day. Advance rates consistently ranged from 180 to 200 m (590 to 660 ft) per week throughout the project.
The hard and abrasive rock required both fine-tuning of the disc cutters and a learning curve with regards to TBM operation. “We overcame the rock by adapting driving parameters to the different geology, cutter wear and vibrations of the machine. We had regular maintenance, but most important of all we got really good at changing the cutters, with times down to 10 minutes per cutter change, which couldn’t have been done without good team work,” said Andersson.
It was the many cutter changes that prompted the close-knit team of LNS and Robbins to look for a better solution. “Extremely hard rock (above 250 MPa/36,300 psi) will always be a great challenge for any cutter. The very special features of the rock encountered combined with the extreme hardness made us go back to the Robbins Cutter Department to develop special cutter rings for the project. These rings increased the cutter life significantly for the project and contributed to the good production,” said Sindre Log, General Manager of Robbins Norway.
The Robbins TBM was launched following Onsite First Time Assembly (OFTA) in January 2014, less than twelve months after contract signing, and was from the outset designed for hard rock conditions. A Measurement While Drilling (MWD) system was included to analyze the ground conditions ahead of the TBM, while probe drilling was done systematically throughout the project. “This is a strong and simple machine ready to tackle hard rock conditions, but also designed to handle softer rock, which allowed for fast excavation. We had good support from competent Robbins field service,” said Andersson.
After all the obstacles, it was clear that the breakthrough ceremony celebrated a triumph of teamwork as well as a new chapter for TBMs in Norway. “Our whole jobsite was gathered for the event: LNS management, representatives from Robbins, and our client Statkraft. People said it was the best breakthrough event they had seen,” said Andersson. Now that tunneling is complete, project owner Statkraft will work to commission the tunnel and fill it with water by spring 2016.