Tunnel Business Magazine

AUG 2018

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TUNNELINGONLINE.COM F E A T U R E S T O RY 3 6 TBM: TUNNEL BUSINESS MAGAZINE // AUGUST 2018 A Renewed Focus on Upgrading Aging Utilities Has Led to a Tunneling Uptick A s one of Canada's oldest cities, eal is looking to get an underground upgrade. In 2018 eal set aside CAD $1.1 billion to repair and update aging roads, water mains and sewers. The need for new utility infrastruc- ture is borne out by the numbers: The average age of water mains in eal is 61 years—at least 20 years older than in other large Canadian cities. An aver- age of 19 breaks occur for every 100 km of water mains in the city eal has responded by stepping up replacements and new construction: In 2006 only 16 km of water mains were replaced annu- ally, but by 2016 this had increased to 389 km. Sewer systems are similarly overtaxed and aging rapidly. In total about CAD $348 million is being devoted to upgrading an- tiquated water and sewer systems, with a further CAD $210 million earmarked for specific projects. Small Diameter Tunneling Ramps Up The influx of Canadian dollars is result- ing in new utility tunnel construction across the city. Some of these projects will be utilizing new technology for the area as well. For example, Contract A-335-4 involves the installation of a new 750 mm diameter wastewater line that will require the first-ever pipe jacking tunnel in rock below the city. The new line will require a 415-m long crossing from a valve chamber at Haut- Anjou Boulevard under Highways 40 and 25 to a valve chamber at Louis-H. La Fontaine Boulevard. Located between 6 to 8 m below the surface, the tunnel runs through limestone with possible hard intrusions, ranging in rock strength fr a UCS. Tunneling will begin in August 2018 with local contrac- tor Drilling using a small diam- eter (1.67 m) hard rock boring machine manufactured by The Robbins Company known as a Rockhead Gripper Shield. Larger projects have also been re- cently complete ember 2015, a 3.0 m diameter Robbins Double Shield ompleted the Rosemont tunnel, a 4.0 km long tunnel through limestone bedrock. The water tunnel was designed to add a buffer into the city's system as needed during peak seasons. The new line utilizes the modernized Rosemont Reservoir, a large structure for potable water built in 1962 but decommissioned 20 years later. Tunneling at Rue Jarry Another recent new water line is the Rue Jarry Water Transmission tunnel. eal commissioned the 4.2 km tunnel below Jarry Street and 24th Avenue following a sequence of events. Large p eal are serviced by a single water main, including an area below Pie-IX Boulevard where a pipeline break was experienced in 2002 in a line around 50 years old. Over the subsequent years multiple inspections were made of the repaired line, and it was determined that another pipeline should be built to operate in parallel with the older line. With the commissioning of the Rue Jarry Tunnel, the old pipe can be taken offline if further repairs are needed without affect- ing water supply. The original bid sent out for the project specified microtunneling and required at least 10 shafts along the alignment. "When Digging Montreal Technology such as Robbins Small Boring Units (SBUs), used in conjunction with ABMs, tackles Montreal's limestone rock. Recent tunnel projects include the 4.0 km long Rosemont water tunnel, bored using a 3.0 m diameter Robbins Double Shield TBM. The influx of Canadian dollars is resulting in new utility tunnel construction across the city, particularly for sewer and water lines to keep up with increasing demands.

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