Cyclic Strength of Undisturbed Sands from Niigata, Japan: Fid-Bau Portal

Cyclic Strength of Undisturbed Sands from Niigata, Japan

M. L. Silver

Standard Penetration Tests, undisturbed field sampling, laboratory index property tests and laboratory cyclic triaxial strength tests were performed on cohesionless soils from Niigata, Japan, to determine why some soil deposits failed by liquefaction while apparently similar deposits remained stable during the 1964 earthquake. Undisturbed samples for testing were obtained from two relatively close-together sites underlain by essentially the same soil layer: a 'river site' where there was severe surface evidence of liquefaction following the 1964 earthquake and a 'road site' where surface evidence of liquefaction was not observed. Undisturbed soil sampling was performed with a newly-designed Japanese large diameter sampler and with an Osterberg sampler, so that U. S. and Japanese sampling procedures could be compared. Field procedures for obtaining small diameter specimens from a large diameter sample were shown to be a meaningful way to avoid sample handling problems. This is especially true if field freezing is also used to immobilize the fabric of the soil. It was found that field freezing with liquid nitrogen and storage of the samples in dry ice was a convenient way to transport and store both large and small specimens. In relatively clean, cohesionless soils which are not susceptible to frost heave, such freezing does not seem to significantly alter the soil fabric or sampled density.