Abstract
Equations to determine parameters of the Hardin-Drnevich and Ramberg-Osgood models that are frequently used in the earthquake response analysis of ground are proposed based on the 482 cyclic shear deformation characteristics tests collected in the Kanto district by means of statistical approach. The Ramberg-Osgood shows worse simulations for fitting the individual test result than the hyperbolic model although it has more parameters, because rate of the increase of the stress is much larger than that of the test. Simulation is worst when damping characteristics are considered in the Ramberg-Osgood model. Then model parameters are expressed as functions with respect to the initial confining stress, plasticity index, fines contents or average grain size or their combinations, and coefficients are evaluated by means of least square method. Here soils are classified based on not only geological ages and depositional conditions but also rough classifications such as sand or clay, Holocene and Pleistocene, etc. It is found that combination of the initial confining stress and plasticity index, and combination of the initial confining stress and average grain size gives best fitting for clayey and sandy soils in almost all classifications.
