Triaxial Compression and Extension Tests for Fiber-Reinforced Silty Sand

Abstract

Inclusion of fibers to improve the engineering properties of compacted soil is becoming an increasingly common practice in geotechnical engineering projects. This study provides a better understanding of the engineering properties of fiber-reinforced soil to confirm the response with different loading conditions. An experimental study for consolidated-undrained (CU) and consolidated-drained (CD) type triaxial compression and extension tests were performed on comparable unreinforced and fiber-reinforced specimens of silty sand to evaluate the effective stress-strain-pore pressure and effective stress-strain-volume change behavior. The results show that fibers increase the effective stress cohesion intercept (c’) and effective stress friction angle (φ’) in both triaxial compression and extension tests. In addition the fiber-reinforced silty sand specimens required a higher pore pressure to maintain the zero volume change in CU triaxial compression tests. The shear strength increases due to the fibers in triaxial extension test was significantly smaller than the strength increases in the triaxial compression test for both undrained and drained loading conditions. Moreover, the reinforced specimens begin to mobilizing the resistance at lower strains in both CD triaxial compression and extension tests. The results also indicate a rational way to evaluate the behavior of the fiber-reinforced silty sand, and therefore certainly warrant a better knowledge along diverse loading paths.