Improvement of strength characteristics for sandy soils by polypropylene fibers (PPF)

Abstract

Sandy soil contains many geotechnical problems, including high permeability, less shear strength, sand dunes, and liquefaction. Therefore, it is necessary to stabilize the sandy soil to improve its engineering properties, either through mechanical or chemical fixations. The mechanical one is done by changing the classification of the soil by mixing it with other types of soils and additives in various gradients. While the chemical fixation is related to the modification of soil properties by adding chemically active substances. In this research, polypropylene fiber PPF with proportions (0.1, 0.3, 0.6, and 1%) was used to study its effect on the physical properties of sandy soils, such as the angle of internal friction φ, shear strength τ, California Bearing Ratio CBR, and permeability k. In this paper the value of φ, τ, and CBR for improved sandy soil increases by 24%, 20%, and 182.2% respectively with adding 0.6% PPF, and decrease in permeability which is estimated to be 26% for 0.1% PPF.