The sinkhole along eastbound Interstate 8 that kept motorists at a crawl during the Thursday evening commute through the College Area was repaired in time for Friday morning rushhour.

Caltrans crews poured what amounted to 40 truckloads of concrete into the hole and had it paved over by 4 a.m., agency spokesman Edward Cartagena said.

“We filled the hole, let the concrete dry and capped it with asphalt to match the rest of the shoulder,” Cartagena said. “We weren’t expecting it to be open until this afternoon. It won’t affect today’s commute.”

A Caltrans geologist studied the sinkhole interior on Thursday and returned Friday, with a hydrologist, to try to determine what caused it. They will look at the possible effects of years of drought followed by this winter’s destructive El Nino rainstorms may have had on the rock and soil in the area, Cartagena said.


The hole started opening up along the right freeway shoulder between College Avenue and Waring Road, below a parking lot at San Diego State University, about 10 a.m.

1 / 8 A workman places a pipe into the large sinkhole next to I-8. (Hayne Palmour IV / San Diego Union-Tribune) 2 / 8 A car-sized sinkhole developed on eastbound I-8 near SDSU. It will affect traffic for some time as work has not yet begun to repair it. (K.C. Alfred) 3 / 8 A car-sized sinkhole developed on eastbound I-8 near SDSU. It will affect traffic for some time as work has not yet begun to repair it. (K.C. Alfred) 4 / 8 Traffic is backed up on eastbound I-8 near SDSU after a car-sized sinkhole developed on the shoulder and right lane. (K.C. Alfred) 5 / 8 Workmen start the work of filling a large sinkhole next to the east bound lanes of I-8. (Hayne Palmour IV / San Diego Union-Tribune) 6 / 8 Two workman places pipes into the sinkhole. (Hayne Palmour IV / San Diego Union-Tribune) 7 / 8 A workman places a pipe into the sinkhole as east bound I-8 traffic passes by at rush hour. (Hayne Palmour IV / San Diego Union-Tribune) 8 / 8 Workmen begin the work of filling a large sinkhole next to the east bound lanes of I-8. (Hayne Palmour IV / San Diego Union-Tribune)

It swallowed dirt and pavement, creating a pit about 20 feet deep and 30 feet by 20 feet across that exposed an irrigation pipe.

The California Highway Patrol and Caltrans crews blocked off three of the five eastbound lanes, then reduced the closure to two lanes, out of concern that the hole would spread under the freeway. The cavity did spread about two feet beneath the freeway pavement.


Cartagena said the irrigation pipe running along the freeway was dry and hadn’t been used since 2006 when a retaining wall replaced landscaping on a slope above the area.

The Waring Road on-ramp to eastbound I-8 also was closed, to try to keep some number of motorists from adding to the congestion past the repair zone. But the evening commute, normally at a crawl past on-ramps through Mission Valley, was made worse for drivers funneled into just three lanes. At one point the line of cars was nearly solid back to Interstate 5.

pauline.repard@sduniontribune.com