Canada’s largest transit expansion project is nearly finished, with completion scheduled for next year. The project includes some incredibly ambitious milestones and incorporates methods and materials normally used in the mining industry – essential when you consider the daunting tasks that are part of the prestigious scheme.
Three of the stations are currently being built with equipment from Finnish mining technology corporation Normet, including up to 18 shotcrete sprayers, concrete transmixers and modified dumper trucks.
During a visit to the Avenue Station site, CTS equipment manager Luis de Espana said, “The reason some stations are built using the mining method instead of cut-and-cover depends on the depth of the stations and the existing utilities. Here, on top of Avenue station, are a vast number of gas, water and power pipes and we are almost 30m below ground level.”
According to de Espana, shotcrete was essential to the project’s success and due to the ground and soil conditions, shotcrete sprayers must be readily available at all times, meaning the mixer trucks run 24/7.
“The plan is to always have one back up sprayer and four transmixers per station,” he explains. “Since we know that we have to spray 12m3 of shotcrete, we bought the large transmixers with 6m3 capacity. We continuously and only use wet-sprayed shotcrete, but we always keep two different dry shotcrete materials on-site as a backup.”
The solution for this was Normet’s Spraymec 8100 VC – an electro-hydraulic self-propelled mobile concrete sprayer used in tunnels up to 10.3m high and 16m wide, with a maximum vertical spraying reach of 14m. The compact design enables operators to work in tunnels with cross-sections from 15 to 140 m2. The operation can be completely carried out by one operator as the strong mechanical arm makes the presence of an assistant unnecessary.
Fitted with the NSP 40 concrete spraying pump, the Spraymec 8100 VC has a theoretical maximum pumping capacity of 40 m3/h, compared to the standard 30 m3/h – making it the perfect solution to the Crosslinx project’s continual need for ready, wet-sprayed shotcrete.
The machine features the latest state-of-the-art control system, the NorSmart2. It also has an onboard compressor with a capacity of 12 m3/min for efficient and high quality sprayed concrete application. Four-wheel drive and four-wheel steering make the sprayer easy to manoeuvre in demanding driving conditions and small spaces, which are certainly present on this project.
These manoeuvrable, easy-to-use solutions for sprayed concrete are essential to this project. According to de Espanda: “The excavation is executed in the segmental tunnelling method: the top heading is excavated in two stages, then the invert in two stages, and then you can see a big cavern, separated in two side drives, and the central drive. It is very important to excavate as fast as possible to maintain a safe tunnel structure. Due to the sand, this excavation needs to be done in small steps.”
The other Normet solution that CTS used is the Utimec LF600 Transmixer. With a practical concrete transport capacity of 5.6 m3, the LF600 is designed for concrete transportation in underground mines and tunnels where the tramming height is 2.6m or more. Concrete drum rotation is hydraulically controlled and the speed ranges between 0 and 13rpm. It features a six-cylinder liquid-cooled turbocharged engine, with a power range between 155 and 190 kW depending on the selected model.
Also, Normet offers an automatic control for transmission, which improves safety and allows the driver to concentrate on observing the surroundings better. The planetary type Dana axles have hydraulically powered dual-circuit oil-immersed multidisc service brakes in both axles.
The vehicle’s suspension system reduces vibration in the cabin and improves the handling of the vehicle. Cabin controls are easy and ergonomic to use, and the multi-information display (MID) provides driving information (such as speed, RPM, temperatures, safety warnings and alarms), which can be recorded for further analysis. The enclosed cabin provides a noise level below 75 dB, ensuring safe and comfortable driving.
The equipment has a reliable 24VDC electric system, which is designed for adverse underground environments. The electric system consists of self-extinguishing wire harnesses with tinned wires and watertight conduits. Additionally, all electrical components are rated at least IP65 class and the hydraulic system is very simple to maintain.
And the final Normet machine to make the lineup for this huge project is the Utimec LF 100 dumper truck is part of Normet’s heavy-duty L-series, typically used in tunnelling projects with medium size cross-sections. The dump box capacity is 12m3 and the tipping angle of the box is 65 degrees. For the Crosslinx project, the box was modified to 14m3 capacity.
The powerful liquid-cooled turbocharged Mercedes-Benz 170 kW Tier3 classified engine provides clean operation and a maximum speed in a horizontal tunnel of 30 km/h. The fully reversible 4 WD with high traction capability ensures safe movement in difficult ground conditions and efficient hydraulic dual-circuit oil-immersed multi-disc brakes provide safe driving. The vehicle has an optional front axle suspension system that improves driving safety and comfort, as well as reducing fatigue.
How has Normet provided the best solutions?
Densely populated urban areas present a number of logistical problems for tunnelling, such as small site entrances and limited space. Crosslinx initially used regular dumper trucks to fill the bins on the shaft ground and lift them to the surface, but the plan was changed to use load haul dumpers (LHD) and Normet dumpers. A vehicle that can handle those 20t muck bins is usually very large, however the trucks from Normet are small as well as strong, making them far more efficient for this project.
According to Jason Huck from Normet Canada: “Normet has helped CTS plan ahead to prevent any downtime but at the same time, if they need us, we are always there to support them. We have a lot of spare parts here on the job site that CTS’ own service staff can, in most cases, repair themselves.”
De Espana concludes: “With Normet as a partner, everything is working perfectly. I wouldn’t expect that, but the commitment from Normet is great.”