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

US Transportation Collection2013PDFTech ReportLi, LinMcHattie, RobertZhang, XiongZhang, MingchuAlaska University Transportation CenterUniversity of Alaska Fairbanks. Institute of Northern Engineering. Department of Civil and Environmental EngineeringUnited States. Federal Highway AdministrationUnited States. Department of Transportation. Research and Innovative Technology AdministrationAlaska. Department of Transportation and Public Facilities. Research, Development, and Technology TransferTransCanada Alaska Company, LCCAlaska. Department of Transportation and Public Facilities. Research, Development, and Technology TransferAlaskaSlopesPermafrostIceFreeze thaw durabilityErosion controlEmbankmentsPhotogrammetrySlope stabilityFrozen soilsFHWA-AK-RD-13-13AUTC #510010 T2-11-05Federal # HPR-4000(112)Permafrost underlies most areas of Alaska. Cuts are usually required to achieve design grades in these ice-rich permafrost areas. However, excavation and exposure of a cut slope will destroy the existing thermal balance and result in degradation of the ice-rich permafrost. Uncontrolled erosion and runoff as well as slope failures on a cut slope resulted from thawed ice-rich permafrost cause environmental distress, project delays, change orders, and claims. The problem had been documented for more than fifty years and still exists. Solutions that are environmentally acceptable, legal, and economically viable are still rare at present, while new and strict environmental laws continue the increasing trend to make long accepted Alaska Department of Transportation and Public Facilities (AKDOT&PF) methods for dealing with ice-rich permafrost either undesirable or completely unacceptable. It is proposed in this research to study several potential thermal erosion mitigation techniques that address the regulatory concerns raised by the current practices and will be particularly effective in controlling erosion from the cut face in the first thaw season. Several test sections will be constructed in the experimental study and monitored to evaluate the effectiveness of different mitigation techniques. Recommendations and guidelines for design, construction, and maintenance will be provided to insure proper application of successfully tested mitigation approaches on future construction projects that require cuts in ice-rich permafrost.125