Roman Hettelingh


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Hettelingh

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Roman

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0000-0002-3119-5619

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Publications 1 - 2 of 2
  • Construction on Slow-Moving Landslides: Effects of Excavation on Neighboring Structures
    Item type: Journal Article
    Hettelingh, Roman; Puzrin, Alexander (2023)
    Journal of Geotechnical and Geoenvironmental Engineering
    In mountainous areas, urban development often takes place on slow-moving ground, which over time may inflict severe damage on buildings and infrastructure. This process can be accelerated significantly by new construction near existing structures. Although for stable ground conditions the problem of excavation-induced damage has been studied extensively, for slow-moving landslides the question of how to reduce damage to neighbors remains open. This paper presents a general finite-element modeling procedure which allows for a full-scale investigation of the landslide excavation problem. The evaluation of structural damage follows an existing approach, in which the effect on the neighboring buildings is deduced from greenfield displacements, using the limiting tensile strain method, correlated with damage categories. The results of the study, which was inspired by real landslide cases, show that failing to estimate the correct compression state of the landslide can lead to significantly higher damage to close neighbors than in the case of a stable slope. Designing the anchors close to the true in situ earth pressure reduces the damage potential, but can result in enormous anchorage costs, if situated in a compressed landslide zone. Excavating farther from neighbors allows for a significant reduction in the required anchor support, which the proposed procedure helps to quantify. Another distinctive feature of excavations within landslides is the development of considerable compressive strains in the sliding direction along the lateral sides of the excavation. It is shown that these compressive strains also have the potential to damage neighboring buildings.
  • Principles of construction on slow-moving landslides
    Item type: Doctoral Thesis
    Hettelingh, Roman (2023)
    Slow-moving landslides are a common phenomenon in mountainous regions. Due to their slow and often unapparent movement, urbanisation has frequently taken place in such areas. The moving ground poses a risk to these buildings, leading to severe damage over their lifetime. Damage has also been found to occur on much shorter time scales, for close neighbours of excavation projects for the construction of a building. This is because the unstable, moving ground, with potentially increased earth pressures, is often not properly considered in the excavation design. In order to investigate this problem, a numerical modelling procedure is developed, suitable for both comprehensive parametric studies and single case analyses. The model incorporates a small portion of a landslide, within which an excavation process with retaining structure and soil anchors is modelled. The resulting deformations around the excavation pit are then correlated to damage on neighbouring buildings, using the limiting tensile strain method and established damage categories. The parametric study, with varying landslide geometry, compression state, soil material parameters, and anchor design, allows for the identification of safe distances from the excavation pit. Moreover, it is found that even in the presence of close neighbours, damage can be avoided by designing anchors for the full in-situ earth pressures. Failure to estimate the correct compression state of the landslide can result in severe damage, highlighting the importance of a thorough field campaign. One reason for the long-term damage evolution on buildings is the elevated earth pressure when a building is located in the compression zone of a landslide. These pressures may rise even higher than the known maximum for the landslide soil mass. Using the kinematic method of limit analysis, a known 2D solution is extended to 3D with the development of two new families of mechanisms. These solutions are complemented with finite element limit analysis calculations. Unfortunately, it is the case that limit analysis solutions represent merely approximations for the present problem, rather than rigorous upper bounds on the true maxima. Therefore, in order to assess their quality of approximation, a slightly adapted version of the numerical finite element model for the excavation problem is employed. The results of an extensive parametric study show that the most influential parameters on the maximum earth pressure are the stiffness of the house, the volumetric behaviour of the soil during shearing, the slope inclination, the soil strength, and the house weight. For reliable and case-specific results, these parameters need to be determined and modelled with high accuracy. Compared to the already existing 2D solution, the new 3D results predict an even higher earth pressure, and therefore highlight the importance of considering 3D effects. Furthermore, the limit analysis results turn out conservative for all the calculated cases in this study, and can represent a practical tool for the design of buildings in landslides.
Publications 1 - 2 of 2