STP892: Compressibility and Settlement of Compacted Fills

    Nwabuokei, SO
    Graduate Assistant and Professor, School of Civil Engineering, Purdue University, West Lafayette, IN

    Lovell, CW
    Graduate Assistant and Professor, School of Civil Engineering, Purdue University, West Lafayette, IN

    Pages: 19    Published: Jan 1986


    Settlement predictions are necessary for compacted fills under a variety of circumstances (e.g., when fills are high, where major structural loads are to be supported, and when the fill materials are clays or weak rocks). As a result of an extensive testing program on both laboratory- and field-compacted materials, a systematic approach to this prediction has been developed. The recommended procedure involves one-dimensional compression testing in three parts.

    The initial vertical strains experienced by the compacted fill are those due to self-weight. The magnitudes of these are highly dependent upon the values of prestress established by the compaction process; however, they occur as rapidly as the fill can be built. The major vertical strains will probably occur as the fill becomes wetter and “softens” in service. The timing of this settlement is uncertain, because it depends upon climatic variables at the site. Materials in the upper portion of the fill will often swell under the low confinement, and the net movement is an appropriate summing of these events with the compressions that occur deeper in the fill. Assuming that the fill becomes essentially saturated in service, further settlements can be produced by loading of the saturated material. The latter response is conventional in nature.

    By testing a series of specimens, with a range of confinements which match those which will be imposed by the prototype fill, representative vertical strains are defined. Integration of these strains over the fill height produces the prediction of movement for the upper surface of the fill. The total testing and prediction technique is illustrated in the paper by example.


    compacted soil, compressibility tests, as-compacted prestress, saturated prestress, regression equations, settlement

    Paper ID: STP34615S

    Committee/Subcommittee: D18.05

    DOI: 10.1520/STP34615S

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