Experimental study on the effect of basalt fiber on the shear behavior of cemented sand

In this study, a series of triaxial tests was performed on a cemented sand improved by adding various contents of basalt fiber. The binding and interfacial interaction between the fiber and cemented sand matrix and the failure model of the interfacial interaction at the sliding surface were examined using scanning electron microscopy (SEM). The triaxial tests show that as the fiber content was increased, the cohesion and residual cohesion first increased and then decreased and the brittleness index decreased, whereas the internal friction angle and residual internal friction angle exhibited no clear variation patterns. Under the optimum fiber content of 0.75%, the cohesion is 406.1 kPa, and the residual cohesion is 145.4 kPa. Compared with cemented sand, the increase is 74.6% and 148.0%, respectively. The SEM tests show that the failure model of the interfacial interaction on the sliding surface included essentially the sliding and pull-out of fibers. The fiber was found to improve shear behavior through the interfacial effect and to affect the failure model through its bridging effect in binding sand particles.