Pre-failure behavior of deep-situated Osaka clay

Great interest has been aroused on deeply-situated Osaka clay since Kobe Ea rthquake in 1994. In this paper is presented the analysis on the results of a series of lab tests on Osaka clay situated from 100 m to 1500 m under th e ground. The wave velocity method, bender element method, LDT and the form ula derived by the authors are used, focus is put on the pre-failure mechan ical behavior of the clay. The analysis shows that, (i) pore-pressure coeff icient B is less than 1.0, (ii) the relationship between shear modulus and Poisson's ratio is not in agreement with that reported before, (iii) the mo dulus measured with LDT is still less than that measured with bender elemen t method, and (iv) there are two threshold strains, within which the clay c an be considered as elastic, and both of them are larger than that reported before.