Evaluation of the effects of soil and earthquake parameters on soil liquefaction

In order to evaluate the soil liquefaction potential and to detect liquefaction potential during an earthquake, there are many criteria, experimental formulas and empirical correlations in which layers containing soils such as sand and silty sand, and soil and seismic parameters which can be acquired with field and laboratory surveys are employed together. It is important to make liquefaction calculations considering all these criteria together. In the thesis study, the effect of soil and earthquake parameters on soil liquefaction was evaluated using different methods and giving theoretical examples with A Microsoft Excels Spreadsheet Software; then the acquired results were discussed and interpreted. In the study, liquefaction calculations were performed with various parameters and presented according to Dobry et al., (1981A) Iwasaki and Tokido (1978) Seed and Idriss (1981). The acquired results clearly demonstrated how the effect of earthquake parameters is important for liquefaction, and change based on the results of the conducted analysis and acceleration values according to the graphics. It was observed that the methods of Dobry et al., (1981), Seed and Idriss (1981) were more reliable among the utilized methods. The fact that the soil feature is sandy and silty, that the sand content is high in the soils and that the underground water level is in 10-meter deep from the soil surface are important commencing condition for liquefaction. The graphics clearly demonstrate how important the effect of earthquake parameters is for liquefaction and that it change based on the results of conducted analysis and acceleration values. According to the results of performed analysis and examinations, we can say that there may be liquefaction after 4.80m of depth or there is a risk of liquefaction if the acceleration value is 0.10g. It is also known that there is a liquefaction risk following the moment that the acceleration value (a,g) is greater than 0.10 and the safety factor becomes lower than 1 so the risk increases. However, we cannot say there will be liquefaction in each soil where the acceleration value is 0.10 and above. Because the factors affecting the liquefaction are required in the soil and the underground water level needs to be close to soil surface, and also the soil should be sandy-silty and have high sand rate. Subsidence problems in the soil following the moment that the acceleration value is greater than 0.10 affect the liquefaction negatively according to analysis result to estimate the subsidence based on the liquefaction.