نوع مقاله : مقاله کامل پژوهشی
نویسنده
استادیار دانشگاه صنعتی کرمانشاه
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسنده [English]
The pre-seismic behavior of natural deposits and artificial (man-made) embankments consisting of granular materials is strongly dependent on their granulation status. In this paper, the small-scale physical models made of dry poor-grained sand and gravel aggregates with low to medium relative densities between 20% and 60% are evaluated. In this study, physical models of granular embankment are equipped with instrumentation to measure the natural frequencies. The inevitable effect of stiffness of the artificial boundaries in physical modeling, i.e., rigid box walls, on frequency responses has been considered. Acceleration sensors are installed to control the effects of grain size and relative density on the values of natural frequencies at the embankment model height. Impact pulse method and extraction of temporal and spectral acceleration histories have been used to estimate the natural frequency responses of embankments with different granular materials. The results of this study show that by increasing the particle size of the poor-grained granular soil and inevitably decreasing its relative density, its natural frequency values (resonance frequencies) decrease. Also, among the geometric factors of the model, the effect of the height of the physical model on the natural frequency is greater than the effects of the length and width of the model. The mathematical relationship between the natural frequency of the model (fn) and the average particle size of the granular material (D50) is calibrated in the parabolic form.
کلیدواژهها [English]
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