Frozen-Soil Classification With Index Testing

Abstract

Classification of frozen soils was first developed by the U.S. Army Corps of Engineers' Cold Regions Research and Engineering Laboratory (CRREL) together with the Division of Building Research, National Research Council, Canada. This visual method of classification was adopted by ASTM in 1983 as designation D4083, currently ASTM D4083-07: Standard Practice for Description of Frozen Soils (Visual-Manual Procedure), Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA. The current visual classification standard does not use any engineering index testing to classify the soils. This leaves the engineer with a qualitative assessment of soil–ice mass type, strength, and stability in which a more conservative and expensive design may be considered and even worse, an under design may occur. The engineer is in need of some index properties that can be readily measured to provide a more objective method to classify the soil–ice mass. This paper investigates the relationship between water content and density to frozen-soil classification. It was found that the water/ice content and dry density within the same frozen-soil class varies significantly, which may lead to different mechanical behavior or thaw settlement. Therefore, reporting the water (ice) content and frozen-soil density together with the frozen-soil classification helps the engineer to better evaluate thaw settlement and assess need for further testing.