A Big Dig tunnel used by motorists to get around a section of highway where a woman was killed by falling ceiling panels was ordered closed Sunday for repairs to the same type of panel.

The tunnel, a quarter-mile-long ramp, needs repairs to panel fixtures, officials said. The work was expected to last at least several days and comes nearly a week after a car carrying Milena Del Valle, 38, was crushed.

Since her death July 10, motorists have been using the now-closed ramp as a detour around the accident scene.

The ramp had been previously identified by Gov. Mitt Romney's inspection teams as a potential trouble spot, said Jon Carlisle, a state Highway Department spokesman.

"We're putting additional connections between the roof and the ceiling panels," he said, adding that the specific number of repair spots was unclear. "We're still working on the engineering."

The closure was expected to snarl traffic even worse, Carlisle said.

Del Valle was killed when 12 tons of falling ceiling panels crushed the passenger side of the car being driven by her husband, Angel Del Valle, as they headed to Logan International Airport.

Connector tunnels in both directions have been closed since then.

After the fatal accident, state and federal investigators have focused on bolts used to hold the drop-ceiling system in place. Each of the concrete slabs suspended above the roadway weighs three tons.

The $14.6 billion Big Dig buried the old elevated Central Artery that used to slice through the city, replacing it with a series of highway tunnels. Although it's been considered an engineering marvel, the most expensive highway project in U.S. history also has also been plagued by leaks, falling debris, cost overruns, delays and problems linked to faulty construction.