Simple Method for Prediction of Undrained Shear Strength of Saturated Soil Subjected to Cyclic Loading

摘要

To evaluate undrained shear strength of saturated soil during undrained cyclic loading without performing a large number of laboratory tests, simple methods for prediction of undrained cyclic strength and strength reduction characteristics were proposed. Analyses of the relationships between properties of soil which is commonly obtained when seismic capacity of irrigation earth dams is evaluated and the characteristics of undrained cyclic strength and strength reduction showed key parameters governing above characteristics. Undrained cyclic strength of gravelly soil and sandy soil increases with an increase in degree of compaction, while that of cohesive soil increases with an increase in clay content. For gravelly soil and sandy soil, when degree of compaction is used as one of explanatory variables, strength reduction characteristics predicted from the model proposed in this paper have good correlation with that obtained from laboratory tests. In contrast, strength reduction characteristics of cohesive soil can be predicted from the model which incorporates dry density, fines content, mean diameter and cohesion as explanatory variables.