A previously developed mathematical model for the prediction of the time-settlement behavior of a sanitary landfill of milled refuse, taking into account the effects of finite deformations, large creep strains, and biological and chemical decomposition of the material with accompanying gas and liquid generation, is reviewed. Modifications and refinements of this model have been made in light of consolidation test data obtained in the present study from the laboratory testing of both raw and laboratory aged milled refuse samples. An apparatus for the consolidation testing of milled refuse was developed in which a back pressure of up to 100 psi can be applied to insure essentially complete saturation of the sample. Laboratory aging of samples was conducted in an insulated chamber maintained at a constant temperature of about 125F. Consolidation tests were performed on 4 raw samples and 11 samples aged for periods of up to 12 months. A general equation of continuity based on the theory of mixture was combined with a rate process function based on the micropore structure to represent the modified model for the time-settlement behavior of this material. Encouraging agreement between the theoretical time-settlement predictions and experimental results was obtained. Limitations of the modified mathematical model and of the experimental program are discussed and a simplified method which is convenient for practical use to represent the time-settlement behavior of milled refuse is discussed.

"Part 4 of 5 parts." Includes bibliographical references. Period covered: 3/1/71 -- 5/31/75. Microfiche.

Part I. Mathematical model for solid waste settlement--Part II. Swelling pressure and permeability in milled refuse--Part III. Anaerobic digestion of milled refuse--Part IV. Consolidation of milled refuse (2 vol.).