Strength and Deformation Behavior of Fiber-Reinforced Cohesive Soil Under Varying Moisture and Compaction States

An experimental study was carried out to investigate the effects of glass fiber reinforcement on the strength and deformation behavior of a cohesive soil under different compaction states by means of unconfined compression tests. The specimens were prepared with varying fiber contents, fiber lengths, dry unit weight and moisture content other than maximum dry unit weight and optimum moisture content of the soil. From the test results, peak strength, failure axial strain, secant modulus and energy absorption capacity of the reinforced soil specimens were calculated and compared with that of the unreinforced soil. The results showed that the relative benefits of fiber reinforcement are highly dependent on the moisture content and dry unit weight of the soil specimens. The peak strength of the reinforced soil specimen increases gradually with increase in dry unit weight, whereas the improvement of peak strength with moisture content occurs up to optimum moisture content. The brittle failure pattern with a single distinct shear plane of the unreinforced soil specimens is gradually transformed to multi-shear failure pattern along with barreling shape at low fiber content, and then to plastic bulging failure with a network of minor fissures at higher fiber content.