GeoStabilization International® assists the Colorado Department of Transportation to restore roadway mobility after two house-sized boulders destroy HWY 145 near Dolores, Colorado over Memorial Day weekend.
On Friday, May 24th, a large-scale rockfall event destroyed a full-width section of Highway 145 between Dolores and Telluride, Colorado, leaving an 8-foot deep trench across both lanes. Among the debris closing the road were two large boulders weighing an estimated 2.3 million pounds and 8.5 million pounds, respectively. The Colorado Department of Transportation (CDOT) was first on the scene to evaluate the damage and determine a course of action. Because the origin of the rockfall was 1,800 slope feet above the roadway, CDOT deployed a drone from Aerial Applications Colorado to gather information for the mitigation efforts.
The event impacted about 150-200 linear feet of roadway, damaged power lines and fencing, and caused minor damage to a vehicle. The story was broadcast nationally and internationally on various news outlets.
CDOT notified GeoStabilization International (GSI) of the event shortly after it occurred, and the GSI team started mobilizing to the site. Working directly with CDOT’s Geohazards Program representatives and engineers from Yeh and Associates, the team assessed the situation and developed a mitigation plan that included rock scaling and boulder downsizing in order to safely reopen the highway. By the following evening, GSI’s Rockfall Remediation Technicians (ferried to the upper slopes by Mountain Blade Runner Helicopter) had completed safety scaling from the source location 1,000 vertical feet above the highway down to the roadway surface along the “runout path” the boulders had created as they rolled down the slope. The following day, GSI and Bedroc Blasting, Inc. from Cortez, Colorado downsized the smaller of the two boulders using controlled blasting. The larger of the two boulders will remain intact at the side of the road. Williams Construction, Inc. mobilized excavators, a hydraulic hammer, and a large loader to further downsize and remove the rock fragments. CDOT Region 5 Maintenance forces played a critical role in the overall operation and were responsible for creating temporary lanes to reopen traffic to Highway 145 on Memorial Day (only three days after the rockfall occurred).
When this event occurred on Friday, initial indications were that the road would be closed “indefinitely.” GSI is proud to have been a part of the CDOT-led team that restored mobility to the corridor only three days after the massive rockfall event occurred.
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A variation of karst sinkhole grouting is the grouting of mined coal seams and workings located below existing infrastructure that exhibit the potential to propagate to the surface and cause sinkholes and/or subsidence.