Experimental Study of Various Techniques to Protect Ice-Rich Cut Slopes

Abstract

Cut slopes are usually required to achieve roadway design grades in the ice-rich permafrost areas in Alaska. However, excavation and exposure of a cut slope destroy the existing thermal balance and result in degradation of ice-rich permafrost. Environmentally acceptable, legal, and economically viable solutions for ice-rich slope protection are still rare. Three potential thermal-erosion mitigation techniques were investigated. Four test sections (Section A: 1 ft wood chips, Section B: coconut blanket, Section C: coconut blanket + Tecco-mesh, and Section D: 1 ft crushed rock as a control section) were constructed at the Dalton Highway 9 Mile Hill during the period of April 17 through April 27, 2013. Temperature and moisture sensors were installed to monitor four test sections and evaluate the effectiveness of the different mitigation techniques. Also, a weather station was built to record climatic information at the test site by April 30, 2013. The filed monitoring period ended on November 11, 2014. No obvious erosion was observed in Sections A and B due to less ice content when compared with Sections C and D which failed one and a half months after construction. The performance of four techniques was discussed in detail.