BOSTON (AP) State transportation officials say a massive 4 ft. (1.2 m) deep hole has opened up about 9 ft. (2.7 m) below the road surface in a Big Dig tunnel in Boston, but poses no danger to drivers.

The roughly 190 ft. (58 m) long sinkhole that has filled with water was caused by settling of the clay around the tunnel.

During construction 11 years ago, contractors chemically froze the soil so it wouldn’t collapse as they dug the tunnel connecting the Massachusetts Turnpike with the Ted Williams Tunnel under train tracks.

Engineers expected settling, but it has happened faster than expected.

It’s expected to cost $15 million to fix the problem, but not until the ground finishes settling by 2014.

The $15 billion Big Dig highway project has been plagued by cost overruns and construction problems.

Today's top stories

Missouri's $284M Chester Bridge Under Construction

Reconstruction of Frank J. Wood Bridge in Maine Under Way

Mecalac Offers Telescopic Wheel Loader to Improve Stability, Mobility in Material Handling Applications

Oshkosh Corporation to Acquire AUSA

Buffalo Looks to Improve, Protect Ralph Wilson Park

Webuild Ready to Rebuild Collapsed Baltimore Bridge

VIDEO: Connecticut Officials Celebrate Rapid Reopening of I-95 Bridge After Destructive Fire

Approximately 650 Bidders Participate in Iron Auction Sale in Midland, North Carolina