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Received Aug 1, 2017; Revised Jan 6, 2018; Accepted Jan 10, 2018
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1. Introduction
The liquefaction phenomenon in a layer of loose sand under dynamic circumstances occurs by the development of excess pore water pressure and decrement of average effective stress which corresponds to a complete loss of shear strength. Liquefaction may cause damages due to bearing capacity loss of strata, large settlements, tilting of structures, and lateral displacements. Condition of soil could be improved by reinforcement to eliminate the liquefaction hazard. Using reinforcement materials such as fibers in soil medium may provide an alternative to reduce the liquefaction potential. Compared to conventional improvement methods using reinforcement, fibers have some advantages like prevention of potential weak planes which mostly form parallel to plane oriented reinforcement and conservation of isotropic shear strength characteristics [1]. The reinforced soil behavior of fibers was studied by researchers in the last decades, but focusing the problem only under static conditions [2–5]. It was revealed that using fiber reinforcement in soil increased the shear strength of soil and improved the ductile behavior and reduced the strength loss observed after the peak strength was achieved. Recently, static liquefaction studies explored the possibility of fiber reinforcement to improve the liquefaction resistance of sand. These studies stated that the occurrence of lateral spreading could be prevented by using fiber reinforcement [6, 7].
Wave propagation during the earthquakes originates undrained shear stresses in the soil medium, the particles of soil experience shear strains, and the pore water pressures are generated in the soil medium. Development of excess pore water pressure decreases the stiffness in response to an applied overburden pressure and triggers a vicious circle that causes larger shear strains and higher pore water pressures. At the final stage, the excess pore water pressure reaches a level of initial overburden pressure, and liquefaction is initiated. Since 1970s, analyzing and modelling of excess pore water pressures in soils under earthquake excitations gained interest among the researchers of geotechnical earthquake engineering. In this paper, along with the findings of this study, other literature is also reviewed and...