Related Links: Highway Administrator's Frozen Soil and Ground Settlement Update to Board of Directors, Aug. 10, 2011 Big Dig's Technical Maual Section on on Jacked-box Tunneling and Ground Freezing Boston’s Big Dig tunnel has one more problem. Thawing from ground-freezing technology used to excavate the I-90 connector system 11 years ago has apparently caused a large swath of soil to settle. Engineers fear that a deep water-filled void may be lurking beneath.The area of concern beneath the I-90 tunnel base slab measures 190 ft long by 60 ft wide, says Frank DePaola, appointed Massachusetts Dept. of Transportation’s new highway administrator
The market is generally healthy and steadily growing, and margins are up for large specialty contractors. Further, advances in design tools and owner demand for collaboration are giving subcontractors a seat at the table early on in projects.