Die Bemessung des vertikalen Schenkels von Winkelstützwänden ist gemäß derzeitiger deutscher Normung für erhöhten Erddruck, d. h. den Mittelwert aus aktivem Erddruck und Erdruhedruck, vorzunehmen. Dieser Ansatz liegt, wie im vorliegenden Aufsatz gezeigt wird, in vielen Fällen deutlich auf der sicheren Seite. Mittels einer numerischen Parameterstudie werden die wesentlichen Einflußfaktoren aufgezeigt. Auf der Grundlage der Ergebnisse wird ein Verfahren vorgeschlagen, das die genauere Festlegung der Erddrucklast unter Berücksichtigung der wesentlichen Einflußgrößen in einfacher Weise ermöglicht.

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Abstract'Fat' clayey soils, containing large proportion of fines (more than 50%) and mixture of aggregates are usually encountered as natural deposits in a high plasticity state. These soils may be used as row material after chemical or mechanical stabilization, in many earthworks applications. The clay content, the amount and size of aggregates, are known to affect the compressibility potential, and thus, the stiffness of the soil when subjected to vertical loads. In this investigation, a comprehensive oedometer testing program was conducted on reconstituted artificial samples, made of various mass proportions of kaolin, sand and gravel. The moisture content of the samples varied accordingly to the percentage of kaolin content in each series, but yielding samples of high plasticity, having the same Atterberg limits. The compressibility was characterized herein by the coefficient of volume compressibility (m v ). The results indicate that, for this type of soils, the compressibility is much more affected by the coarser matrix (ratio of the mass percentage of the gravel to the mass percentage of sand G/S) rather than the percentage of clay content. Based on the observations made, a chart is proposed for a quick estimation of the compressibility potential of fat clays.

Backfilled L-shaped retaining walls are considered as complex types of geotechnical structures, which are particularized by the fact that they are not only supported by the soil, as is the case with foundations, but also loaded by the soil. Actual design methodology does not take into account the construction sequences which simulate the process by which the soil and the retaining wall are brought together. However, in reality, at least during the backfilling process, the retaining wall undergoes many displacements that are not so far considered in the design. In the present investigation, the influence of the construction sequences on the behaviour of an L-shaped stiff retaining wall is investigated with a numerical model. For validating the proposed numerical model, reference was made to the results of a centrifuge experiment conducted on a reduced prototype. The numerical analysis shows that for the type of wall and soil investigated, considerable displacements of the wall (rotation and translation) occur during the backfilling process. The rotational movement of the wall is not occurring around the toe as it is usually assumed in design practices, but it follows a total displacement path of the toe. It is recommended that a better estimation of the rotation (s) of the wall is necessary to reach the state in which active earth pressure can be fully mobilized.

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