Shear strength response of glass fibre-reinforced sand with varying compacted relative density

Triaxial compression tests were conducted to investigate the response to loading of glass fibre-reinforced sandy soil of varying relative densities (35, 65 and 85%). The fibre diameter was 0.15 mm, varying in length from 10 to 30 mm, and in content from 0 to 4% by weight of dry soil. The tests were performed at confining pressures ranging from 100 to 400 kPa. The separate and joint effects of fibre content, fibre length and confining pressure on the strength and deformation characteristics of the specimens were evaluated. The strength of specimens increases up to an optimum fibre content value of 3 or 4% depending on length. Fibre reinforcement has restricted the bulging and shear zones for specimens of all relative densities. A non-linear regression model has been developed for predicting the shear strength of reinforced soil, and scaling law has been employed for using the laboratory results for field application.