Determination of Subsurface Conditions of Frozen Ground Layers Using Surface Waves at Three Permafrost Sites in Fairbanks, Alaska, U.S.A

摘要

The Phase I research study investigated the feasibility of a new seismic technique, the Spectral-Analysis-of-Surface-Waves (SASW) method, for determining the thicknesses and layering of frozen and thawed ground in permafrost regions. The capabilities of the SASW method were investigated at three permafrost sites in Fairbanks, Alaska with varying soil and thawed/frozen profiles during early May 1988, when thawing of the seasonally active frozen zone was well along. Geotechnical borings and downhole seismic tests were performed to evaluate the accuracy of the SASW method in delineating thawed (lower velocity, soft) versus frozen (higher velocity, stiff) soil strata. Results demonstrate that the SASW method can delineate thawed and frozen ground with significantly greater detail and accuracy than previously obtained by existing surface geophysical methods without drilling borings.