Physical and mechanical properties of waste ground at inert waste landfills

The physical and mechanical properties of waste ground were examined at 14 locations across 4 inert waste landfills in Japan with the goal of establishing a safe and cost-effective design methodology specific to inert waste landfills. Composition analysis, basic physical properties, angle of repose, CASPOL impact value tests, and in situ direct shear tests were conducted. Inert wastes were comprised of three main components: fibrous, granular, and soil-like content, and their compositions varied between 3.6-54%, 13-45%, and 43-74%, respectively. As the fibrous content and age after reclamation increased, the water content increased but the percentage air voids decreased. The impact value (Ia), which is an indicator of the bearing capacity, increased as the dry density increased. For all locations, the angle of repose after avalanche (alpha a) was found between 34 and 44 degrees. In direct shear tests, the cohesion (c) and internal angle of friction (phi) ranged from 2 to 21 kN/m(2) and 22-59 degrees, respectively. The shear stresses obtained from these c and phi values were higher than those for the municipal solid wastes, particularly for landfills with fibrous fractions ranging 14-31% under a normal stress of 25.55 kN/m(2). c increased and phi decreased as the dry density increased. The correlation calculated for c and phi with Ia for inert waste landfill were c = 4.10I(a) - 21.32 and phi = - 4.61I(a) + 82.37. Finally, the utilization of the results obtained in this study is discussed in three design stages: planning, landfilling, and future expansion.

Automated summary

The study on physical and mechanical properties of waste ground in inert waste landfills in Japan reveals the influence of fibrous content and dry density on the design and planning, providing valuable guidance for safe and cost-effective methodologies.