Highway 93 Slope Stability Analysis, Golden, CO

The Colorado Department of Transportation (CDOT) has requested an assessment of the stability and potential mitigation of a landslide that developed on the east facing slope of State Highway 93, near Golden, Colorado (refer to Figure 1). The initial slope cut for the bypass was 35-ft-deep. Slow movement of the landslide began during construction and was then stabilized.  In 1992, movement occurred again in the landslide, resulting in damages to the newly opened road. CDOT installed a drainage system to lower the high ground-water levels and re-graded the head scarp of the slide. Then, in 1993, a higher than normal amount of precipitation raised the ground-water levels and reactivated the landslide. Seeps and springs were flowing from the toe of the landslide and the tension crack at the head scarp was completely saturated by Magpie Creek at the time of failure. Approximately 500,000 cubic yards of material moved and closed the southbound lane of Highway 93. CDOT is currently considering additional mitigation alternatives to minimize the hazard to the road.

Slope Stability Analysis Slope Stability Figures