Comparison of Mechanical Properties ofFiber-Reinforced Sand under Triaxial Compressionand Direct Shear

Abstract

This research investigates the behavior of sandreinforced with polypropylene fiber. To do this, 40 directshear tests and 40 triaxial tests were performed on thecoastal beaches of Babolsar, a city in the North of Iran. Theeffect of parameters such as fiber content, length of fiberand normal or confining pressure on the behavior of Babolsarsand have been studied. In this study, four various fibercontents (0, 0.25, 0.5 and 1 percent), three different lengthsof fiber (6, 12 and 18 mm) and four normal or confiningpressures (50, 100, 200 and 400 kPa) have been employed.The test results show that fiber inclusion has a significanteffect on the behavior of sand. In both direct shear and triaxialtests, the addition of fibers improved shear strengthparameters (C, '), increased peak shear strength and axialstrain at failure, and also limited the amount of post-peakreduction in shear resistance. The comparison of the testresults revealed that due to better fiber orientation towardthe direction of principal tensile strain in triaxial test ascompared to direct shear tests, the fiber efficiency and itseffect on soil behavior is much more significant in triaxialspecimens.

Keywords

• randomly distributed fibers
• strength parameters
• soil behavior
• strength behavior
• fiber orientation