Fort Point Channel Deep Soil Mixing

The Fort Point Channel is a maritime channel that separates South Boston from Downtown Boston, feeding into the Boston Harbor. The Southern part of the channel has been gradually filled in for use by the South Bay Rail Yard and various highways. 

In the 1980s, public works projects were planned, stimulating interest in the Fort Point area and the South Boston waterfront. These projects were underway by the final decade of the 20th century. While a Central Artery highway project tunneled through Boston’s downtown, another underground connection tunneled from the Mass Pike, under the Channel, the Fort Point district and Boston Harbor to connect with Logan Airport. The MBTA began construction of a public transportation transitway under the Fort Point Channel and the Massachusetts Convention Center Authority began construction of its Convention & Exhibition Center at Fort Point’s eastern edge. This CASHMAN JV project was one of many ongoing at the time. 


  • Soil stabilization performed on an unprecedented scale, to a depth of 120 feet. Required replacement of both mainline railroad and traffic bridges. 
  • Installation of 300,000 square feet of steel sheet piling and four cofferdams. 
  • Extensive dredging, demolition, and excavation in a site that had experienced more than two centuries of waterfront construction. 
  • Construction of a 400-ft-long cut-and-cover slurry wall supported tunnel structure. 
  • Work performed in a high traffic downtown area adjacent to railroad, mass transit, postal terminal, and the world headquarters of The Gillette Company. 

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Massachusetts Highway Department
$237 Million (Cashman $152M)
Aug. 1996 – Jun. 2001