Investigation on the interfacial mechanical behavior of wave-shaped fiber reinforced soil by pullout test

Fiber reinforcement benefit is dominated by the interfacial mechanical behavior between fiber surface and soil matrix. In this study, a new wave-shaped fiber (WF) was proposed as an alternative reinforcement to improve the interfacial mechanical interactions. In order to quantify the interfacial shear strength, a single fiber pullout test device was developed and a series of single fiber pullout tests were carried out on both conventional straight fiber (SF) and WF reinforced soil. Moreover, the effects of compact water content and dry density on the interfacial shear strength were investigated. It is found that the pullout response significantly depends on the morphology of fibers. The pullout curves of SF show typical mono-peak pattern, while those of WF show typical multi-peaks pattern. The maximum interfacial shear strength of WF reinforced soil is much higher than that of SF reinforced soil, indicating that the WF can better enhance the interfacial mechanical interactions and fiber reinforcement benefit. With increasing pullout displacement, the interfacial shear strength at each peak decreases exponentially. The interfacial shear strength of WF reinforced soil significantly depends on compact conditions. It increases linearly with decreasing water content, while exponentially with increasing dry density.