{'fraction_non_alphanumeric': 0.0178103719224725, 'fraction_numerical': 0.0, 'mean_word_length': 5.945454545454545, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
EFFECT OF FIBERS ON THE COMPRESSIVE AND TENSILE STRENGTHS OF SAND CONSIDERING FAILURE MODE

: In geotechnical engineering, fiber reinforcement for improving the stability and strength of soils is of considerable interest. According to previous studies, fibers enhance compressive strength significantly, whereas the contribution of fibers in extension is limited. However, this phenomenon has not been analyzed comprehensively. Therefore, conventional triaxial compression and extension tests were conducted under both drained and undrained conditions on fiber-reinforced sand specimens to elucidate the influence of fibers on tensile strength. The compression behavior was significantly influenced by the presence of fibers and confining pressure, independent of the drainage conditions. However, in the extension experiments, the properties of the fiber-reinforced sand under drained conditions differed from those of unreinforced specimens. The tensile strength of the fiber-reinforced sand was relatively enhanced under undrained conditions. Both unreinforced and fiber-reinforced sands experienced deformation throughout the entire height of the specimen, and their central regions bulged under loading conditions. With an increase in confining pressure under unloading conditions, the unreinforced sand specimen developed a double “necking” shear band in the center with more pronounced strain localization. In contrast, the failure modes of fiber-reinforced sand in drained conditions were characterized by strain localization and shear bands transferred to the bottom part of specimens. According to the experimental results and their repeatability, a conventional triaxial extension test may be insufficient to evaluate tensile strength accurately. In addition, a possible explanation for the fiber-sand interaction mechanism has been proposed based on the obtained results and failure mode analysis.