In Situ Investigation of Liquefied Gravels at Seward, Alaska

Dynamic in situ penetration tests and crosshole shear wave velocity measurements were performed in deep alluvial gravel deposits at Seward, Alaska that were shaken and reportedly liquefied by the March 27, 1964 Alaska Earthquake. Two sizes each of split spoon and dynamic cone penetrometers were driven into the gravels near the mouth of the Resurrection River that had exhibited settlement and lateral spreading consequent to earthquake shaking. Two safety hammers of different size were employed, and the energy delivered using various hammer and penetrometer combinations was measured throughout all tests, with the exception of two duplicate tests of the larger sampler and dynamic cone. Limited measurements were also made of hammer velocity, using a radar system developed for that purpose, to allow for kinetic energy determination. Disturbed soil samples were evaluated for classification and to determine stratigraphy. This paper summarizes the procedures used at the Seward site, as well as preliminary correlation of penetration resistance, measured by alternate means and normalized for overburden stress and driving energy, and shear wave velocity in the coarse-grained deposits. Comparisons are also made to penetration resistance measurements made by the Alaska Highway Department immediately following the 1964 earthquake.