جستجوی مقالات مرتبط با کلیدواژه "soil behavior" در نشریات گروه "عمران"

It has been a long time since crude oil products and, their derivatives have contaminated soil. Crude oil contamination is an unavoidable consequence of rapid overpopulation and, the industrialization process. Crude oil contamination can change soil geotechnical behavior and, affect soil strength, foundation-bearing capacity, and slope stability. On the other hand, “mini-cone’ tests have rapidly become the most famous type of on-site testing. Because, the mini cone is a fast and, economical experiment that continuously provides information on the geological layout and, the proper assessment of soil properties. This paper compares the changes in the tip and, side resistance of the mini-cone. There are mixed soils of two types of fine-grained sand with 10%, 20%, 30%, 40%, and 50% kaolinite clay, which were tested with 4% and, 8% crude oil and, different moisture contents. These investigations have been done with the physical modeling method and, calculating the value of Ic, focusing on the mini-con data. Results showed that the tip and, the side resistances of the “mini-cone” were decreased in mixed soils with increasing crude oil content and, changes in moisture contents. Except for two sandy soils mixed with 10% and, 20% clay, which were mixed with 4% crude oil. There was an increase in tip and, side resistance due to the lack of the maximum density in the laboratory chamber compared to the standard Proctor test. Also, with these changes, Ic calculation found that the soil's behavior shifted towards finer soils.

To study and predict the behavior of flexible pavement over expansive soils, a pavement structure was subjected to different laboratory and fieldwork experiments. The existing pavement was replaced and designed based on California Bearing Ratio (CBR) method, with a new one, and subjected to the traffic from various number of load cycles from 12.1 up to 155.52 kcycles of standard axle load (80 kN) through dual wheel assembly over a 6-month period. As the preliminary step, the deflection measurements were taken at the asphalt surface layer, using a Total station at different distances as function of truckload applications. The numerical analysis is carried out with the Finite Element software package PLAXIS version 2012. In the new model, the calculation of the transferred pressure to the pavement through contact area of tires is 3D it was turned into a 2D problem, and the pavement was subjected to a static loading using a ratio factor of dynamic additional charge. The materials’ behavior was simulated with nonlinear models: Mohr–Coulomb (MC) for pavement layers and soft-soil model (SSM) for the expansive subgrade, in saturated drained and undrained conditions. The results indicate that displacements under static loading in saturated drained conditions and when non-linear materials are present are the closest to field measured deflections.