Pipeline work causes I-70 sinkhole
A void that resulted after a natural gas pipeline was installed beneath Interstate 70 caused a sinkhole on the roadway this week in the Rulison area.
State highway workers first noticed the sinkhole Wednesday night just east of Exit 81. Both lanes of eastbound I-70 were closed, and traffic was rerouted on U.S. Highway 6 between Exit 81 and Exit 87 at west Rifle.
Single-lane closures of westbound I-70 were required Thursday to allow for drilling of test bores beneath westbound lanes.
Colorado Department of Transportation spokesperson Nancy Shanks said those test bores found additional voids where the Williams Production pipeline crosses the interstate. Those voids will have to be filled by drilling down to the pipeline and doing high-pressure grouting using a cement-like material, she said.
Williams spokeswoman Donna Gray said the costs associated with the problem and its repair will be borne by the pipeline contractor, whom she declined to identify.
Gray said the pipeline work beneath the highway was done early this year, but the 20-inch-diameter pipe hadn’t yet been pressurized with gas.
A left eastbound lane will be closed today for further work, and the closure may have to continue into next week during daytime hours.
Crews had excavated the sinkhole to about 35 feet in diameter and 8 feet deep to examine the subsurface and look for other voids. They filled the excavated area Thursday.
The pipeline was installed 20 feet below the highway. Shanks said the test bores also revealed water around the pipeline.
Neither Shanks nor Gray immediately knew what kinds of costs are associated with the sinkhole repair and grouting work.
Shanks said Williams responded quickly to the incident, showing up on the scene Wednesday night even before state traffic-control crews could arrive. Williams provided equipment for the paving operation.