
A massive "sinkhole" at least 4 feet deep and up to 190 feet long has created a "void" under the Interstate 90 connector tunnel in the problem-plagued Big Dig, adding to a growing list of engineering failures that include a deadly ceiling collapse, dangerously unstable light fixtures and lethal railings, state transportation officials revealed yesterday.
Transportation officials insist there is no risk of a new catastrophic collapse in the tunnel - the same one where Milena Del Valle was killed by a 3-ton slab of concrete five years ago - but some critics said they aren't convinced.
"You hear this and think, 'What's coming next?' " asked Rep. Peter Durant (R-Spencer), a Transportation Committee member calling for a probe of the latest Big Dig fiasco. "This is just another in a long line of problems for this project."
The gap 9 feet under the tunnel's roadway, filled with water and resembling a subterranean pond, was caused by an unexpected degree of settling of the clay soil around the tunnel as a result of a pioneering technique called "ground freezing" while contractors dug under the train tracks serving South Station.











