GROUNDFORCE has supplied a range of specialist equipment, including MP80, Mega Brace, Maxi Brace and double-acting Mechshore braces to install a new large-diameter pipeline at a Yorkshire wastewater treatment works.
The contract, at the Naburn WWTW, involves the laying of a new 1.6m diameter steel pipe to carry sewage sludge across the site to the final settlement tanks where it is prepared for de-watering and disposal. Improvements are being led by Black & Veatch as principal contractor.
The route of the 100m long pipeline crosses several existing services which the new pipe must run beneath. This has meant digging down as deep as 7m to get enough clearance.
“The pipeline passes through the location of old sludge lagoons and the ground condition here is very poor,” says Richard Kent, Black & Veatch section engineer. “Approximately half the trench had to be supported with steel sheet piles which needed to be heavily braced.”
The shallower stretches of the trench were lined with standard trench sheets and supported with double-acting Mechshore braces but where the pipe dived down to clear an existing FST feed pipe crossing the new excavation, heavier equipment was required. “The deeper section was lined with sheet piles and three levels of frame were installed to support the sides,” says Groundforce technical services engineer Oliver Smith.
