Laboratory Studies on the Effect of Vertical Gravel Column Drains on Liquefaction Potential

Abstract: In recent years deadly earthquakes in seismic areas have caused special concerns regarding liquefaction phenomenon by researchers and specialists. Excess pore water pressure in loose sediments may cause phenomena such as boiling, shearing strength and dynamic stiffness reduction and lateral movements cause difficulties. Many remedial methods such as soil replacement with proper materials, in situ compaction of the soil, soil improvement using in situ grouting, and column drains have been designed and used so far to overcome liquefaction phenomenon. For existing areas with liquefaction potentials and high depths, soil replacement method is generally impossible. Vertical drain method which is both economical and easy in execution can be an alternative way to be used. In this article, three series of 1-g shaking table laboratory tests were carried out and vertical column gravel drains are modeled. In the models, various importing acceleration with variation in column gravel drains distances are studied. For modeling, Anzali shore sand situated in the north of Iran was used. Results showed that the behavior of gravel column drains varies with variation in imported seismic acceleration, and the output of this method for reduction of liquefaction potential is affected considerably. The results also showed that the conventional design method criteria to determine distances between the drain columns are very conservative. Keywords: Column drains, liquefaction, shaking table, modeling.