Today, the use of waste tires mixed with soil has been expanded in various geotechnical projects to absorb and reduce the vibration caused by seismic and dynamic loads. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, 1-g shaking table tests were carried out, and the effects of important parameter like loading frequency on the dynamic behavior of mixtures were investigated. Tire powders were added to the sand with 5%, 10%, 15% and 20% in gravimetric basis and with a relative density of zero were subjected to sinusoidal loading at frequencies of 0.5, 1, 2, 3, 5, 7 and 9 Hz and input acceleration of 0.1g and 0.3g. The results showed that in all cases, the increase in frequency in the same cycles increased the shear modulus and the damping ratio. Also, with increasing shear strain, the shear modulus of the mixture decreased, but the damping ratio increased. On the other hand, by increasing the tire powder, the value of the shear modulus is reduced, but the amount of damping ratio is increased.
Dynamic soil properties are important parameters for the design of structures subjected to various dynamic/cyclic loading such as earthquake which can be obtained by in situ and laboratory measurements. Numerous empirical and mathematical models have been proposed to predict the dynamic properties of soils, including maximum shear modulus (Gmax), normalized shear modulus (G/Gmax - γ) curve, reference shear strain (γr), minimum damping ratio (Dmin) and damping ratio (D - γ) curve. However, the majority of the existing models were proposed for specific soil types, loading characteristics, initial soil fabrics and strain ranges. This paper proposes five universal models to estimate the Gmax, γr and Dmin values, and also G/Gmax - γ and D - γ curves using a database that contains 117 tests on 5 different granular soils. The proposed models include the effect of grading characteristics, void ratio, mean effective confining pressure, consolidation stress ratio (KC) and specimen preparation method. The models are validated using experimental data from previous studies for granular soils. The results indicate that the proposed models are capable of evaluating the dynamic properties of granular soil., Meysam Bayat., and Obsahuje bibliografii