When you’re faced with a hard rock tunnel on your next small hydro project, which tunneling method works best? Intake tunnels can be at diameters as small as 2 meters and at steep grades of up to 45 degrees. Compared with the conventionally used method of Drill & Blast, small diameter tunneling machines offer increased production rates and reduction in cross section, among other benefits. The uniquely designed machines are engineered to take on steep gradients, and can bore tunnels kilometers long with minimal impacts to the surrounding environment.
In this complimentary, 60-minute webinar we discuss the use of small diameter tunneling machines on projects throughout Norway, where their popularity is increasing, as well as the method’s suitability on projects worldwide. Listen in on our conversation with Robbins Norway General Manager and Civil Engineer Sindre Log as we discuss recommendations for small hydro tunnels in hard rock. Join us for a live Q&A session at the end to get a thorough answer from our expert speaker.
When you’re faced with a hard rock tunnel where there are expected significant sections under high water pressure, which tunneling method do you choose?
While Slurry Shield tunneling has a long history of addressing this problem, this method has not always been problem free. Another highly effective method exists that can lower costs and risks: Non-continuous Pressurized (NCP) TBM Tunneling with a shielded machine. When used in rock with a comprehensive grouting program or sequential advance in EPB mode, NCP TBMs have proven that they can successfully navigate high water pressures safely and effectively.
In this complimentary, 45 minute webinar we debate the pros and cons of Slurry and NCP TBMs, and look at case studies of both types of machines in hard rock under high water pressures. Listen in on our conversation with Robbins President Lok Home and Brad Grothen P.E., Robbins Technical Director, as we discuss recommendations and the future of tunneling in rock under water pressure.
France’s recently completed Galerie des Janots was the scene of some unforeseen challenges. During excavation with a Main Beam TBM, crews encountered a stalagmite studded 8,000 cubic meter cavern, and also a 4,500 cubic meter cavity directly under the bore path. In addition to the two large and uncharted caverns, there were also karst cavities of a multitude of sizes found throughout boring. What exactly did the crew do to beat the odds and power through?
For the answer, be sure to listen in as Detlef Jordan, Robbins Sales Manager Europe, goes into detail about the obstacles, lessons learned, and recommendations for future tunnels in karst conditions.
Difficult ground doesn’t begin to describe the challenges overcome at a recent tunnel in central Turkey. The breakthrough of a 5.5 m diameter Robbins Crossover XRE TBM at the Gerede Water Transmission Tunnel was a feat of modern construction. The 9 km leg was the final section of the 31.6 km long water supply line bored through what is widely considered to be Turkey’s most challenging geology: from 48 fault zones to water pressures up to 26 bar, the ground put the machine and the crew to the test.
Listen in on the conversation with Robbins Vice President Doug Harding as we find out how the unique TBM design and experienced crew overcame a gamut of challenges.
Nepal’s first TBM-driven tunnel was a success by any standard: The Robbins Double Shield machine bored up to 1,200 meters a month and finished the Bheri Babai Diversion Multipurpose Project nearly a year early. But how were crews able to bore so quickly? And what made the contractor and owner ultimately decide to use a TBM for the first time?
Watch our complimentary 30-minute webinar with Brad Grothen P.E., Robbins Technical Director, and Missy Isaman P.E., Robbins Project Engineer, as we discuss the challenges, lessons learned, and recommendations for future tunnels in mountainous geology.
Modern TBMs are data-driven systems, from ground investigation tools ahead of the machine to touch-screen technology in operator’s cabins, to integration with programs on the surface. Today’s TBMs, paired with cutting-edge data collection and monitoring, can efficiently bore in even the most demanding circumstances.
In this complimentary 40-minute webinar, Robbins VP of Operations Steve Chorley and Aaron McClellan, Tunnel Superintendent III for Kiewit Underground, will explore the latest and greatest innovations in technology for TBMs. Nearly all the parameters of a TBM can be monitored today, and this data can be transmitted via radiating coaxial cables to offices on the surface or even mobile phones. Simple observations, such as cutterhead RPM and penetration rate in a given geology, can result in altered operational parameters and reduced thrust that can speed up advance and increase cutter life. All that is required is proactive analysis by management and engineers, and good communication with the TBM operator.
TBM maintenance: it’s one of the most important factors predicting project success, but it is often treated with less importance than it deserves. Experience shows, however, that maintenance plays just as much a part in the excavation rates as the proper TBM design. Regular maintenance can keep future rebuild costs low and keep equipment efficiency high while maximizing advance rates. Conversely, a lack of maintenance, improper operation, and/or severe ground conditions can result in undue wear and slow advance rates. In a worst-case scenario, it can even require rescuing and refurbishing of a TBM.
In this 40-minute complimentary webinar, Robbins Sales Manager Europe Detlef Jordan and iPS Tunnel Manager Barrie Willis will discuss case studies of both optimal and suboptimal maintenance and operation of TBMs. Suboptimal examples will be discussed where TBM maintenance was insufficient and required rescuing of the machine once it became stuck or immobile. Optimal case studies will form a guideline for recommended machine maintenance to prevent the substantial damage that can occur. Rebuild strategies for recovered TBMs in various adverse conditions will also be discussed.
Rapid excavation is considered by many to be the ultimate goal in TBM tunneling—machines that reliably complete projects on time (or early) with faster advance rates, regardless of conditions. However, speeding up a project schedule is not as straightforward as pushing a machine harder, working longer hours, or increasing your crew size. The entire project schedule, from initial investigations to the design process, must be considered.
In this succinct, complimentary 40-minute presentation designed to better fit your workday, Robbins Engineering Director Brad Grothen and Elisa Comis, Associate at McMillen Jacobs, discuss what rapid excavation really looks like in the field including case studies on TBM design and real-world examples of project scheduling.
If you’re tunneling in mixed face conditions, where any combination of rock and soil may be present in the tunnel cross section, you expect the project to be a challenge. When variability is a constant, things like surface settlement, abrasive wear on your TBM, and the proper ground conditioning are a concern. Despite these variables, your project can still be a success. With the right technology, crew, and operating methods, consistent TBM advance rates are achievable in even the most variable conditions.
In this complimentary 60-minute webinar, Robbins Vice President Doug Harding and Engineer Greg Michaelson will explore mixed face conditions, delving into recent case studies of EPB and Crossover TBMs in the field. Harding and Michaelson will make recommendations based on proven designs and methods, drawing from the experience of our knowledgeable field service personnel. Whether you’re a contractor operating the TBM, a consultant specifying the equipment, or an owner with an upcoming project, consistent excavation is possible in variable geology.
If you’ve ever faced mountainous tunneling conditions, then you know what it is to face the unknown. Most deep tunnels under high cover encounter some unexpected conditions, whether its fault zones, squeezing ground, or rock bursting. Without the proper planning, crew experience, and TBM design, these challenges can quickly halt a TBM in its path. From severe squeezing that can trap a shielded machine in place to highly pressurized rock bursts that can damage the TBM itself, mountainous tunneling can get serious fast.
So how do you keep your TBM moving when the going gets tough? Spend 60 minutes with our tunneling professionals and learn from the best in this complimentary webinar—the first in our 2018 series. Using real case studies, we’ll discuss some of the most difficult conditions encountered in our decades of tunneling in the field. Find out how to overcome obstacles while keeping your downtime to a minimum and your crew safe.
- The Green Alternative: Small Hydro Machines for Clean Energy
- To Grout or Not to Grout?
- TBM Tunneling in Karst Conditions
- Boring Through 48 Fault Zones and 26 Bar Pressure
- Over 1,200 Meters per Month in Himalayan Geology