Geotechnik

Zur Bewältigung der Herausforderungen der alternden Infrastruktur und des Fachkräftemangels kann die Digitalisierung durch Effizienzsteigerungen einen wesentlichen Beitrag leisten. Die Zielsetzung ist die Realisierung eines Digitalen Zwillings der Infrastruktur, der das Bauwerksmanagement sowohl auf technischer als auch auf administrativer Ebene effizienter gestaltet. Die Bauwerksüberwachung erfolgt über die Erfassung physischer Veränderungen und deren Übertragung auf das digitale Abbild, das eine Analyse der Ursachen ermöglicht. Zur Erreichung dieser Ziele werden digitale Methoden wie Building Information Modelling (BIM) und Ontologien eingesetzt. Ontologien sind maschineninterpretierbare Modelle, die Bauwerksinformationen sowie das zugrunde liegende Expertenwissen vereinen und somit eine effizientere Administration ermöglichen. BIM ermöglicht die Verknüpfung semantischer, alphanumerischer und geometrischer Informationen. Der bidirektionale Informationsaustausch zwischen realen Brückenbauwerken und digitalem Abbild ist der Kern des Digitalen Zwillings. Dieser Ansatz wird bislang nur in einer begrenzten Anzahl von Projekten teilweise umgesetzt, weshalb ein Blick auf die unterschiedlichen Vorgehensweisen mit ihren Vor‐ und Nachteilen sowie die damit verbundenen Herausforderungen sinnvoll ist. Es wird eine Vorgehensweise für die Erstellung von Teilsystemen Digitaler Zwillinge von Brückenbauwerken auf Basis von Structural Health Monitoring und Ontologien vorgestellt.

Information and recommendations of the working group 1.6 ‘Numerics in Geotechnics’ on the calculation of groundwater flow and its effect on stability using the FEM. In this article, DGGT Working Group 1.6 ‘Numerics in Geotechnics’ provides information and recommendations on the calculation of groundwater flow and its effect on the overall stability using numerical methods, with special attention to the finite element method. These supplement the existing general recommendations of Working Group 1.6 and the recommendations for numerical analysis of the overall stability using the FEM. Important principles for the numerical analysis of saturated as well as partially saturated groundwater flow are topics of this article. The associated initial and boundary conditions as well as simplified calculation models are also discussed. Furthermore, physical properties of boundary value problems, such as their time dependency and the type of coupling between the mechanical behavior of the grain structure and the groundwater flow, are used for classification into analysis types. Finally, recommendations are given to support the selection of an analysis type and to find an adequate strategy for the calculation. Some further recommendations deal with the selection which of the numerous influences from groundwater flow on the results of FEM calculations should be taken into account, particularly for determining the overall stability. To conclude, guidelines for plausibility checking of the calculation results are provided.

Soil plugging in open-ended piles is likely to occur in dense sandy soils which has been the subject of numerous scientific investigations. In contrast, the plugging behaviour in clayey soils is relatively unknown. In this paper an analytical approach to determine the soil plug resistance and its development during jacking in clayey soils is proposed. The new approach was developed using numerical simulations and was validated by back-calculating a field test from the literature. A total stress approach for the numerical simulations was chosen. The values calculated with the analytical formulas and the numerical solutions as well as the measurements from field tests are in very good agreement, given the high complexity of the interactions between pile and soil. Both the plug resistance and the plug height can be calculated during the jacking process. Further research is required to refine the proposed approach for soil plug resistance evaluation, as the proposed method is believed to enhance the understanding of occurring mechanisms.