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WJ News

Latest News and Updates from WJ Groundwater and across the Industry.

LRT Extension Project in Toronto

Dan Carpenter October 27, 2023

WJ keep Toronto Moving

The expansion of the Toronto Light Rail Transit (LRT) network has provided WJ with a steady stream of work since WJ Canada was formed in 2016, work which continues to this day.

Throughout 2022 WJ undertook a variety of pumping tests and other hydrogeological investigations at a number of key sites along the LRT alignment. Alongside these investigatory works, WJ have provided robust dewatering solutions to maximize the drawdown at the Tunnel Boring Machine (TBM) intervention sites.

TBM Interventions

These interventions are locations along the alignment where maintenance is performed on the cutting face of the TBM, and therefore, for safety reasons, zero hydrostatic pressure is required. This requites an extensive and robust dewatering system – something WJ are experts in providing.

In addition to investigatory and dewatering works, an extensive array of groundwater monitoring wells was installed along the alignment to be used for pre-commissioning testing and system monitoring.

LOCATION: Toronto

Eglinton Station, TTC interchange, Toronto

Dan Carpenter April 25, 2021

Eglinton Crosstown LRT

The Eglinton Crosstown Light Rail Transit (ECLRT) project consists of almost 20km of light rail transit running through the heart of Toronto, from Mount Dennis in the West to Kennedy in the East.

The project has been one of the most technically challenging construction projects in Toronto’s recent history, and one of the largest scale dewatering projects WJ have undertaken globally in our 40 year history and one that we are proud to have been part of.

Eglinton Station – A Technical and Logistical Challenge

One of our most recent involvements in the project is on the Eglinton Interchange Station. Eglinton Station is one of the busiest stations on the existing TTC subway, and the new Eglinton Crosstown LRT line will be constructed underneath the existing live subway tunnel. As if this doesn’t already make for an extremely challenging project, the area around Eglinton Station is already heavily developed with numerous tall condo and office towers around one of the most congested intersections in the city.

Fortunately WJ are accustomed to this technically and logistically challenging projects, and installed a number of inclined large diameter deepwells and wellpoints in to the underlying strata to lower the standing groundwater level.

Meeting project constraints

WJ had to work very closely with consultants and engineers from the many stakeholders involved in the project to demonstrate that dewatering underneath this critical piece of Toronto’s infrastructure could reduce the overall risk for the project and allow for time-saving shoring alternatives to be considered for the TTC subway box construction.

Another Successful Project

The WJ Canada team is very proud to be a part of the successful dewatering and excavation beneath the Yonge-Eglinton interchange.

LOCATION: Toronto
MAIN CONTRACTOR: Metrolinx

Finch West LRT Project, Toronto

Dan Carpenter February 8, 2021

The Dewatering Vendor of Choice for Toronto LRT Projects

The success of the Eglinton Crosstown LRT (Light Rail Transit) project (also known as Line 5) in Toronto, where we have provided dewatering services to great effect on 12 of the 14 stations, has led to WJ becoming the dewatering vendor of choice for large LRT projects in the city.

Finch West LRT

Building on the success of this project, WJ have recently begun work on the Finch West LRT project. The Finch West Project (also known as Line 6) continues the expansion of public transit services in Toronto and is expected to carry some 40,000 passengers per day by 2031. Our initial works on the project will cover the two new underground station that are due to be constructed: the new terminus at Humber College and the new interchange terminus at Finch West, where the new line will connect with the Line 2 extension to York University.

Finch West Station

The Finch West Station includes a deep connection to the existing subway station and an underground track crossing – in short a deeply complex project, that will require the installation of deep wells, wellpoints and eductor wells. Fortunately these types of projects are second nature to WJ and perfectly demonstrate our creative and flexible approach to providing successful and efficient dewatering solutions that we have shown on thousands of project in Canada and elsewhere across the globe!

Humber College Station

The Humber College station, located adjacent to Highway 27 will be another opportunity to demonstrate many of the dewatering techniques that were used to great effect on the deep excavations of the Eglinton Crosstown project.

We are proud to be given the opportunity to contribute to this exciting project, and the continued expansion of public transit projects in Toronto, and look forward to its successful completion, and having the opportunity to hop on board!

LOCATION: Toronto
CLIENT: Metrolinx

WJ wellpoint installation at UOIT September 2019

Eductor systems for PATH Toronto

WJ Group Admin September 9, 2020

PATH Toronto – the background

Torontonians have long considered near incessant construction on the arterial roads of the city a part of everyday life in a vibrant and ever growing metropolis.

In order to try and minimize this disruption and as part of the development of the new lake front South Core district, a new pedestrian tunnel was required to be constructed underneath York Street, forming part of the PATH pedestrian walkway system that spans more than 30km of downtown Toronto.

Phase 1

Phase 1 of the new tunnel project, under the southbound lanes of York Street, was beset by extensive issues with the dewatering contractor unable to control the seepage flows in to the excavations. This lead to project delays and frustrations for commuters, the City and the General Contractor. One of the most important skills for those in the construction industry is learning from previous projects, therefore for the second Phase of the project, under the northbound lanes, the client was determined to recoup the lost time and therefore adopted a different approach to the project – part of which involved getting WJ on board!

Meeting project constraints

The General Contractor, PCL, the second largest in Canada, chose to partner with WJ for the tunnel dewatering works upon the recommendations of the structural consultants for the project.

Due to the nature of the site, a small compact rig with a capability of drilling with water flush was essential, therefore we used our trusty SM5 drilling rig to install an eductor dewatering system in Toronto’s characteristic low permeability silty sandy lake deposits which overly the deeper bedrock.

The eductor system was chosen as, based on our extensive experience of working in downtown Toronto, it is best suited to the generally low permeability soils with occasional high permeability layers that are generally encountered.

Ahead of schedule

This installation method and system was so successful we were able to complete our works AHEAD of schedule, and this, coupled with the absence of problematic groundwater in the challenging reclaimed land of the South Core district, enabled the client to make up much of the time lost during the first phase of the works.

LOCATION: Toronto
MAIN CONTRACTOR: PCL

“This installation method and system was so successful we were able to complete our works AHEAD of schedule.”

Sump Pit Completion at Caledonia Station

WJ Group Admin July 18, 2019

The Eglinton Crosstown represents the largest transit expansion in Canada. It will completely change how residents and visitors in Toronto get around this great city. 19 kilometres of new light rail – 10km underground – that starts in the west end and travels right through the city to the east end, with 25 new stations and stops linking to 54 bus routes, three subway stations and various GO transit lines. That means shorter commutes, reliable and convenient transit and cleaner air.

But that kind of huge infrastructure project doesn’t come without more than its fair share of challenges! This was exactly the case at the Caledonia Station site. The ground conditions we encountered there were among the most challenging we’ve had to deal with in WJ’s long and successful involvement with the Eglinton project. However, we were confident that given our decades of experience and industry-leading practices, we were up for the challenge!

Eglinton Crosstown Caledonia Station dewatering

Multiple clay layers ran through the site, cutting up the aquifer into many different pieces. Factor in a massive 30m deep excavation, shored by soldier pile and lagging, and we had all the ingredients for a dewatering nightmare.

After coming in to rescue project developers, CTS, from an inferior dewatering system that couldn’t tackle these site conditions, WJ got to work with Crosslinx to uncover these layers. Our expert water management consultants deciphered the geology of ancient glacial lake bottom deposits that lay buried deep underground across Toronto.

However, in the world of dewatering, clay is clay. No matter how thin, a continuous layer can quickly change dewatering requirements.

Our deductions were proved correct when we uncovered a 1-inch thick layer of clay across the entire site. Working tireless to dewater each and every layer, WJ battled the water towards the base of the sump pit. From there. our sump pit dewatering actions provided a site suitable for CTS to complete their excavation and commence construction of the station from the bottom-up.

“WJ helped the Caledonia team through some very challenging conditions at Caledonia. They were committed and worked with us every step of the way. WJ’s can-do attitude was refreshing and much appreciated on this difficult and challenging site.”

– Daniel Sanchez, Project Manager, Caledonia and Keelesdale Stations.

LOCATION: Oakwood Station, Eglinton Crosstown Light Rail Transit
CLIENT: Crosslinx Transit Solutions
MAIN CONTRACTOR: CTS

Quick Turnaround Dewatering at Science Centre Station

WJ Group Admin July 18, 2019

Being the largest transit expansion in Canada, with significant on-going disruption to Toronto’s population, any delay to the development of Eglinton Crosstown LRT is not welcome news. Especially when that delay is totally unexpected. That’s exactly what happened when the construction crew discovered groundwater where there wasn’t supposed to be any!

Early one morning, WJ Canada received a call for help. The CTS construction team, working at the Science Centre Station, encountered groundwater at the bottom of the excavation. The Science Centre Station is the longest excavation on the entire Eglinton Crosstown project, at 800m in length, with the deepest part being underneath Don Mills Road.

According to a previous hydrogeological investigation, there was not supposed to be water present. Yet, to their surprise, as the CTS crew approached the bottom of an aquifer on a clay Till, they were greeted by approximately 1m of water. This prevented the last section of excavation and concrete placement. It also meant a potentially serious delay to the project!

Once we’d received CTS’s call for help, WJ was on-site within just a few days and we wasted no time in getting straight to work. This involved drilling inclined well-points on both the north and south side of the excavation. We worked from the bottom of the shaft, through the lagging wall, and got the entire system commissioned in record time.

Just two weeks after receiving their call for help, WJ had dewatered the Science Centre Station site. CTS were able to resume excavation in dry conditions. Within 3 months, CTS had completed all concrete and waterproofing systems and WJ was able to decommission the system.

“WJ came in on very short notice and executed a professional and effective dewatering solution. Their solution was cost effective and efficient as the wells were short and installed from the base of the excavation. The solution was tailored to our needs as they allowed us to complete our station build-back all the while remaining functional behind the waterproofing membrane. I would recommend WJ to any contractor in need of a dewatering partner.”

– Diego Ocampo, Project Manager, Science Centre Station

LOCATION: Oakwood Station, Eglinton Crosstown Light Rail Transit
CLIENT: Crosslinx Transit Solutions
MAIN CONTRACTOR: CTS

Cross Cut Completion at Oakwood Station

WJ Group Admin July 18, 2019

The Eglinton Crosstown Light Rail Transit (ECLRT) project consists of 19.7 km of light rail transit running along Eglinton Avenue from Mount Dennis in the west to Kennedy in the east. The project is being designed and constructed by Crosslinx Transit Solutions (CTS).

With such an important and flagship infrastructure project, under constant public scrutiny, given the build disruption to local communities, the stakes were high. CTS needed a true water management partner who would work with them right through to the end. And that’s where WJ came in.

WJ was called in from the UK to take a look at dewatering requirements of the Eglinton Crosstown Project – a challenging commission, which combines difficult dewatering conditions with innovative construction techniques. Several of the stations within the Eglinton project are being constructed using a unique soil mining technique, known as the New Austrian Tunnelling Method. This meant that our dewatering solutions had to be just as innovative in order to succeed.

Right from the start, the Oakwood main entrance access (called the cross-cut) was flagged as the most challenging aspect of the project. A silty, low-permeability soil matrix that fines towards the bottom of the excavation was located just above a clay interface. Using, wellpoints, eductors, and deep wells, installed from the road surface and from confined spaces in TBM tunnels and mined caverns, WJ was able to complete this substantial dewatering feat, without any delay to the CTS mining schedule.