Results of large-scale cyclic triaxial tests on the mixed material of Rudbar dam core

ABSTRACT: Earth dams may be subjected to low-period, high frequency loads such those from earthquakes. Clayey gravel soils often used in the core of such dams are difficult to test due to the large size of the gravel particles since representative samples of such soils contain grains that exceed the maximum size allowable in conventional triaxial apparatus. Due to the higher cost of large-scale triaxial apparatus and the substantially longer time required for saturation and testing of large samples, smaller samples are often tested to determine the behavior of such soils. In the current study, results from large-scale triaxial tests on the mixed material of the core of an earth are presented. Saturation of each sample took more than one month, and was followed by consolidation and undrained cyclic loading. Degradation of shear modulus and change in damping ratio obtained from conventional size triaxial tests and resonant column tests on the same material are also compared with results of large scale tests.