Abstract
Undrained cyclic triaxial tests and drained triaxial compression tests were conducted on undisturbed samples of diluvial dense gravelly soils obtained by in-situ freeze sampling at four sites. These test results, together with test results by other researchers indicate that undrained cyclic strengths of gravelly soils depend not only on the modified blow count of penetration tests but also on effective confining pressure. By considering the effect of effective confining pressure on undrained cyclic strength, a method to evaluate undrained cyclic strength of natural gravelly deposits using the blow count of Large Penetration Test (LPT) is proposed. Furthermore, the possibility of evaluating undrained cyclic strength of natural gravelly deposits using initial shear modulus was investigated. It was found that although initial shear modulus can be used for this purpose, the accuracy is much less than that based on LPT penetration resistance.
