This job was part of The Colorado Department of Transportation’s project to reconnect Little Thompson River to Muggins Gulch. Since 1937, the river has been channeled into US 36’s roadside ditch, where floods have washed out the river channel and caused substantial damage to the roadway embankment. This drainage structure contributes to the permanent solution of directing the river path beneath the highway to minimize erosion damage and road closures in the event of future flooding.
Drill Tech constructed an 11′ diameter horseshoe tunnel for the East Culvert under the historic US 36, approximately 60′ below the road. Although the tunnel method was originally specified as shield, part of Drill Tech’s Value Engineering changed the method to conventional excavation utilizing an AM75 roadheader and mini-excavator due to the high risk of encountering large granitic boulders within the tunnel envelope. The project was successfully completed on schedule despite multiple challenges including encountering boulders in excess of 7′ diameter and multiple shutdowns due to nearby forest fires.
Contract Value:
$3.4M
Delivery Method:
Bid-Build
Property Owner:
The Colorado Department of Transportation
General Contractor:
Flatiron