Standsicherheitsnachweis in der tiefen Gleitfuge unter Berücksichtigung von Strömungskräften

Overall stability of anchored walls using sliding block method with due consideration of flow forces.

The paper presents the effect of additional groundwater flow forces that arise as a result of lowering of ground water behind a permeable retaining wall on the overall stability based on the sliding block method. This load situation cannot be solved with current computer programs for the overall stability analysis. The literature also deals with this topic very scarcely. Depending on the permeability of the underground, the groundwater table after drawdown may lie outside the active sliding wedge of a retaining wall, but within the sliding block to be considered for the overall stability of an anchored wall. In such case, the required anchor length is usually calculated in practice assuming a full groundwater table before drawdown. On the basis of practical examples (multi-anchored walls in a multi-layered underground), the article shows that the anchor length determined in such a way may not necessarily lie on the safe side. A concept to account for the groundwater flow forces in the overall stability (sliding block method) has been developed for anchored walls in the geotechnical department of the Zentrale Technik, Ed. Züblin AG. The approach is currently used in practical projects and is presented in detail in the following.