But the report said the road could settle by as much as 12 inches in a “small portion” of the landfill near the intersection with Sohier Road. To prevent that settling, “aggregate piers” would be constructed by drilling holes into the landfill material, filling the holes with crushed stone and compacting the stone.
The report said the pier technique has been used often in New England and the Greater Boston area to control ground settlement. Haley & Aldrich, one of the companies that prepared the report, has been involved in about 25 such projects over the last 10 years, it said.
The area in question was used as a city landfill from 1946 to 1961 and contains burnt wood, coal ash and household materials such as colored glass, plastic parts, metal, paint chips and newspapers, according to the report. A 2009 study concluded that development of the site “posed no significant risk of harm to public safety,” the report said.
The report said any excavated material would be consolidated on the site or on the adjacent CEA parcel. Measures would also be taken to prevent buildup of methane gas below paved areas.
Staff writer Paul Leighton can be reached at 978-338-2675 or email@example.com.