ABSTRACT
This paper examines the influence of parallel grading on the hydro-mechanical characteristics of unsaturated fouled ballast by conducting a series of triaxial compression tests and water retentivety tests on various fresh and fouled ballasts with parallel grading in unsaturated conditions. As the results, it was revealed that soil-water characteristic curves and relationships between degree of saturation and peak shear strength were seriously affected by intrusion of fouling materials into fresh ballast, and that the hydro-mechanical characteristics of unsaturated fouled ballast was influenced by the average grain size even if employing the parallel gradation of grain size distribution. These results indicate that for the precise evaluation of the mechanical property of unsaturated fouled ballast, it is important to carefully interpret the test results using the parallel grading geomaterials.
