Not only is it one of the most expensive wastewater treatment projects ever undertaken by the City of Hamilton, installing the Dickenson Road Trunk Sanitary Sewer requires a mix of construction techniques, notably tunnel boring under hard Niagara Escarpment rock for a large portion of the 10 kilometre route.
Designed by IBI Group, the approximately $106-million project is intended to support the development of the planned 551-hectare Airport Employment Growth District immediately adjacent the John C. Munro Hamilton International Airport.
According to the city, the growth district will support the airport as “as an important infrastructure and economic driver.”
Design of the sewer began in 2019 and then last October general contractor Technicore Underground Inc. began onsite mobilization.
The contractor will install the sewer from the existing Centennial Trunk Sanitary Sewer at Regional Road 56 to Upper James Street.
Three different construction techniques will be used, says city project manager David Mullen.
It involves the tunnel boring installation of 5,636 metres of 1,500 millimetre sewer pipe through the Niagara Escarpment; two sections of the same diameter pipe by micro-tunnelling through mixed face and soft ground for a total of 1,850 metres; and an open cut stretch at the very north end of the construction zone of 2,529 metres of 1,200 millimetre pipe.
Those methods were determined by a geotechnical and hydrogeological study which took into account factors such as the sewer depth, area traffic, utility conflicts and the barriers posed by the escarpment, he says.
“The slope of the (escarpment) drops,” says Mullen, explaining why the micro-tunneling will be used about the mid-way point between two stretches of the rock tunnel boring and then again just before the open cut area, which is comprised of clay soil.
As for that open cut stretch, which will end at Upper James Street at the western boundary of the construction zone, it will be undertaken by subcontractor Amico Construction. That phase is slated to start May 1.
There will be a total of nine tunnel and micro-tunnel shafts along the route.
Technicore has been conducting staging work at shaft one at Regional Road 56 and is also drilling through the overburden and rock to install 36, 13.7-metre-deep, one-metre-diameter concrete caissons to form the support system at shaft two.
The tunnel shafts will range from seven to 16 metres in depth and from six to eight metres in diameter, says Mullen.
In the rock tunnel sections a two-pass system will be used. Technicore will mine the tunnel first and then install the pipe between the shafts afterwards.
Start date for the tunnelling is still to be determined at this time, he says.
Some of the challenges the city and the contractor will have to contend with include disruption to the area, groundwater impacts on natural features and private wells, and ensuring that all Hamilton Conservation Authority regulations are adhered to, he says.
The project is scheduled for completion in November 2026.
Recent Comments
comments for this post are closed