Pore pressure development in sand specimens reinforced with polypropylene fibers

7th International Conference on Earthquake Geotechnical Engineering (ICEGE) -- JUN 17-20, 2019 -- Rome, ITALYWOS:000623514302090In this study, polypropylene fibers are used as reinforcing elements in sand specimens. The objective of this paper is to evaluate the performance of fibers in the liquefaction behavior of sands. The relative densities of the specimens were 30% and 70%. A series of tests were run under stress-controlled and undrained conditions and under 100 kPa of confining pressure to observe the dynamic behavior of the sand specimens with or without fibers. Unreinforced specimens were prepared as a control group. The amount of fibers added were 0.25%, 0.5%, and 1% by means of the dry mass of the sand. The fibers were mono-filament type and two different lengths of fibers were used in the tests which are 6 mm and 12 mm, respectively. The relationship between cyclic stress ratios (CSR) and the number of cycles and the curves of pore (water) pressures were achieved for the fiber reinforced sands. The pore pressure curves presented in up-to-date analytical models of fiber reinforced soil were compared with the pore pressure curves of fiber reinforced sands of this study. As a result, the findings of this study provide an insight to the behavior of clean and fiber reinforced sands under dynamic loading cycles. As a result, it was found that the number of loading cycles acting on the fiber reinforced specimens is the dominant factor in the excess pore pressure generation.Int Soc Soil Mech & Geotechn Engn, European Assoc Earthquake Engn, Int Geosynthet So