Subsurface Void the Latest Problem for Boston's Beleaguered Big Dig

“The long, 190-ft sunken area of the Big Dig tunnel is no little pot hole and the length indicates a large mass of water,” Jaroszewicz says. When freezing 130 ft below the surface, you are likely to find many different aquifers that could freeze, he says.

“There are lots of aquifers near the ocean,” he says. “When you are deep like that the ground is potentially 40° F, only 8° above freezing, so there is not much temperature differential for every pound of water.”

Johanna Knapschaefer, ENR’s New England Special Correspondent, has been writing about trends in design and construction of buildings, bridges, tunnels and other infrastructure for more than a decade. She also profiles award-winning industry leaders and delves into broader construction issues such as workforce training, worker safety and health, climate change remediation and emerging offshore wind and tidal energy developments. Over the past two decades, her articles have appeared in Architectural Record, BusinessWeek, the Boston Globe, American Banker, Modern Metals, BusinessNH Magazine, Pittsburgh Magazine and many other publications. Johanna is fluent in Japanese, and taught English and academic writing in the Science and Engineering Department of Ritsumeikan University, Kyoto, while living in Japan for eight years.

When not writing, Johanna enjoys mountain climbing, singing and playing her Spanish guitar.