Robbins TBM uncovers Spectacular Cavern at Galerie des Janots
Apr 20, 2018
Workhorse Machine makes progress in Difficult Ground.
A rebuilt Robbins 3.5 m (11.5 ft) diameter Main Beam TBM has yet another milestone to add to its storied career: an unexpected cavern, encountered and successfully passed through. Contractor Eiffage Civil Engineering is operating the machine, which launched in 2017 for the Galerie des Janots project in La Ciotat, France.
The cavern, studded with stalactites and stalagmites and measuring 8,000 cubic meters (283,000 cubic ft) in size, was grazed on the tunneling operation’s left side. The crew named the cavern “grotte Marie Lesimple” after their site geologist.
“We hit the corner of it. To cross it, we had to erect a 4 m (13 ft) high wall of concrete so the TBM would have something to grip against,” explained Marc Dhiersat, Project Director of Galerie des Janots for Eiffage. A small door allowed access inside the cavity, which formed naturally at a point 60 m (200 ft) below the surface. The TBM was started up and was able to successfully navigate out of the cavern in eight strokes without significant downtime to the operation.
“This is certainly unusual, to come across a cavern of this size and significance. It is somewhat related to the geology, with karstic and volcanic formations having the most potential for underground cavities,” said Detlef Jordan, Robbins Sales Manager Europe. Karst cavities were a known risk during the bore, but the cavern was not shown in vertical borehole reports conducted from the surface along the alignment.
A further 1.8 km (1.1 mi) will need to be tunneled before the 2.8 km (1.7 mi) tunnel is complete. “It is possible there could be more unknown caverns. We have a geotechnical BEAM system on the machine, and are conducting probe drilling, shotcreting, and maintenance in a separate shift,” said Dhiersat. The BEAM system, standing for Bore-tunneling Electrical Ahead Monitoring, is a ground prediction technique using focused electricity-induced polarization to detect anomalies ahead of the TBM.
The crew encountered difficult ground conditions early on in the bore, consisting of limestone with powdery clays. “When the machine is boring it does well. We have good production and it’s a good machine for hard rock. But sometimes it’s not hard rock that we encounter,” said Dhiersat.
The weak rock and clay conditions necessitated ground support including resin-anchored bolts and rings in bad ground, topped with a 10 to 15 cm (4 to 6 in) thick layer of shotcrete. Despite five months of poor ground conditions, Eiffage is optimistic that conditions will improve and the tunnel will be complete in the next four to five months.
Galerie des Janots is one of the fourteen operations designed to save water and protect resources, which are being carried out by the Aix-Marseille-Provence metropolis, the water agency Rhône Mediterranean Corsica, and the State Government. The future Janots gallery will replace existing pipelines currently located in a railway tunnel—these original pipes have significant deficiencies with estimated water losses of 500,000 cubic meters (132 million gallons) per year.
The completed tunnel will pass under Le Parc National des Calanques, with cover between 15 and 180 meters (50 to 600 ft), in order to replace the pipes that are currently being utilized for the water supply networks. “The current pipes have a capacity of transit limited to 330 liters (87 gallons) per second, which is largely insufficient in the summer period. The objective of the operation is to secure the lines and increase capacity to 440 liters (116 gallons) per second,” said Dhiersat.
More News and Articles
Mar 27, 2024
News
USU Study Looks at Water Main Break Rates in the U.S. and Canada
Report Highlights Correlation Between Material and Diameter
Mar 26, 2024
News
Update BE-21: New Material in Course and Modules on Trenchless Pipe Installation
Online training on the topic of pipeline installation in civil engineering: Trenchless technology for underground drainage construction can be a resource-efficient, environmentally friendly, time-saving, and cost-effective alternative to open cut methods. The UNITRACC e-learning course "Utility Tunnelling" has been enhanced …
Mar 25, 2024
Article
Bacteria as a new weapon in wastewater treatment
In early November, San Diego based startup Aquacycl officially opened its first European office and test center at the Water Campus in Leeuwarden. The Netherlands Foreign Investment Agency (NFIA) and the Investment and Development Agency for the Northern Netherlands (NOM) …
Mar 22, 2024
News
A superior HDD offering
Building on its relationships with leading horizontal directional drilling companies, TRACTO Australia has delivered three new rigs to operator Superior HDD.
Mar 20, 2024
News
New portable water filtration technology could improve access to clean drinking water worldwide
The University of Texas at Austin has developed an injectable water filtration system with the aim to aid the over two billion people worldwide who are without clean drinking water.
Mar 18, 2024
News
Global Student Innovation Challenge Calls on Next-Generation Leaders to Tackle Water Security
High School and University Students Worldwide Invited to Expand Water Access and Community Resilience
Mar 15, 2024
News
New water treatment wins Prestigious Award
Introducing a advancement in water treatment, developed by Cardiff University researchers in collaboration with Origin Aqua, the FreeOxTM technology has garnered acclaim by winning a prestigious challenge award at the World Water Tech Innovation Summit. This single-step process not only …
Mar 13, 2024
News
Satellite-based river monitoring technique could provide early warning of flooding
A satellite-based method for monitoring the flow of rivers from orbit could provide a valuable early warning system for flood risk, University of Glasgow researchers have claimed.
Mar 11, 2024
News
Revitalising infrastructure with HDD
Through the use of horizontal directional drilling, TasWater is delivering a new sewer pipeline to improve sewer and stormwater transfer capacity in Launceston, Tasmania.
Mar 06, 2024
News
Picking up the pace on climate action: Building momentum from COP28
At the halfway point of the Paris Agreement, the legally binding international treaty on climate action, average global temperatures are already hitting 1.8°C above pre-industrial levels and future projections are stark. At COP28 in December, we could not escape the reality …
Mar 01, 2024
News
Luminescent sensor detects ‘forever chemical’ pollution in water
Researchers in the UK and Germany have developed a new approach for detecting pollution from ‘forever chemicals’ in water through luminescence.
Feb 28, 2024
Article
BETT installation demonstrating GHG emissions reduction of wastewater treatment
This study presents BioElectrochemical Treatment Technology (BETT) as a new wastewater management solution toward the Net-Zero future. The results reported herein were collected from a BETT pilot system installed at a large brewery in Los Angeles, CA, United States processing …
Contact
The Robbins Company
29100 Hall Street
OH 44139 Solon
United States
Phone:
+1 440 248 3303
Fax:
+1 440 248 1702