Sharif Digital Repository

Soil Liquefaction is a phenomenon corresponding to earthquake in which granular soil loses most of its strength in seismic loading. In this study, cyclic simple shear tests were performed for evaluating the effect of non-plastic fines on liquefaction resistance of Firuzkouh sand. Firuzkouh sand is uniform and is classified as SP in USCS. Firuzkouh silt was used as Non-plastic fine. Tests were performed under constant vertical load and undrained conditions on cylindrical specimens 7 cm in diameter and 2.2 cm in height. Samples were prepared using wet tamping method. All specimens were saturated following the standard back pressure method until the Skempton B-value was at least 0.96. Samples... 

Small strain shear modulus, Gmax, is one of the most important parameters for characterization of the behavior of earth structures subjected to static or dynamic loading conditions. This research presents an experimental laboratory study on the effect of non-plastic fines content and hydraulic hysteresis on the maximum shear modulus of unsaturated sand-silt mixtures. In this regard, clean Firoozkuh No. 161 silica sand which is classified as poorly graded uniform sand was mixed with different percentages of silica non-plastic silt. A set of bender element tests were planned to carry out implementing two modified triaxial devices. The modifications on these two apparatus were to add HAV... 

Regarding the existing contrary in the literature in relation to the effect of plastic fine on sand liquefaction behaviour, we decided to study this effect. Amounts of 5, 15, and 25 percent of two types of plastic fine, Kaolinite with PI=19 and Bentonite with PI=116 added to Firoozkooh Sand and 68 stress controlled tests were conducted using cyclic simple shear apparatus. In all teste the frequency of shear loading and consolidating vertical effective stress were constant and 0.1 Ht and 100 kPa respectively. Reaching excess pore water pressure ratio to the maximum value (r_u=Max) and reaching double amplitude shear strain to the value of 5% have been considered as liquefaction critera. In...