Alexander Puzrin

Last Name

Puzrin

First Name

Alexander

ORCID

0000-0002-9566-8841

Organisational unit

03691 - Puzrin, Alexander / Puzrin, Alexander

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Publications 1 - 10 of 49

Material point method for large deformation seismic response analysis
Kohler, Marc; Stoecklin, Andreas; Puzrin, Alexander (2022)
ECCOMAS Congress 2022 - 8th European Congress on Computational Methods in Applied Sciences and Engineering
Landslides triggered by earthquakes are one of the major seismic hazards and can cause large damages and fatalities. The material point method (MPM) has become a popular technique to model such large mass movements. A limitation of existing MPM implementations is the lack of appropriate boundary conditions to perform seismic response analysis of slopes. To bridge this gap, an extension to the basic MPM framework is presented for simulating the seismic triggering and subsequent collapse of slopes within a single analysis step. The concepts of a compliant base boundary and free-field columns are applied within the MPM framework enabling the direct application of input ground motions and accounting for the absorption of outgoing waves.
Landslide influence zone - a hidden hazard
Puzrin, Alexander (2021)
Géotechnique
Inspired by two practical cases in Switzerland, the paper investigates a problem of elevated earth pressures downslope of existing landslides. This problem is relevant for both permanent landslides andone-time events, and of particular practical interest is the area of the stable slope just below the landslide high-pressure compression zone. Intuitively, there should be a transition zone, within which high landslide pressures subside to the far field (at rest) earth pressures in the stable slope. How large is this transition zone and how fast do the earth pressures decrease away from the slide? The paper proposes a basic mechanism of the downhill pressure transfer within the stable part of the slope below a landslide.The mechanism combines the failure at the bottom of the unstable part of the slope with progressive growth of the slip surface into the stable part, accounting for the groundwater flow and potential presence of embedded structures. It allows the determination of the dimensions of the ‘landslide influence zone’ below the landslide and the lateral earth pressures within it, providing some insights fordesign considerations and future hazard mapping.
The slip surface mechanism of delayed failure of the Brumadinho tailings dam in 2019
Zhu, Fangyuan; Zhang, Wangcheng; Puzrin, Alexander (2024)
Communications Earth & Environment
The 2019 Feijão dam failure in Brumadinho, Brazil, claimed 270 lives and caused enormous environmental damage. A special feature of this failure was that it took place three years after the tailings disposal was terminated, which should have allowed sufficient time for the material to consolidate and increase its strength. Here we propose a basic physical mechanism of a delayed slip surface growth along weak layers of fine tailings within the dam body. Using accurate numerical modelling of all stages of the evolution of the Feijão dam, we show how this growth was preconditioned by dam construction and tailings discharge history and further driven by creep deformation during the post-closing stage, until the slip surfaces reached their critical length, resulting in their unstable propagation and the rapid collapse of the entire dam. Main factors controlling the time of failure have been identified, facilitating future risk assessment for decommissioned tailings dams.
Growth of slip surfaces in 3D conical slopes
Klein, Boaz; Puzrin, Alexander (2021)
International Journal for Numerical and Analytical Methods in Geomechanics
Out-of-plane curvature of real submarine slopes imposes limitations on applicability of existing planar criteria for catastrophic growth of slip surfaces. In this paper, the growth of an initially weakened zone in three-dimensional (3D) convex and concave slopes is investigated using the process zone approach. The geometry of the problem is presented in a curvilinear coordinate system for which the governing equations for the three-dimensional slip surface growth are derived. Solution of these equations for an axisymmetric problem is obtained both analytically and numerically (using a finite differences scheme) and benchmarked against Coupled Eulerian-Lagrangian finite element simulations. It is shown that the application of the planar slope solution to conical slopes constitutes an overestimation of the slope's stability. The closed form criteria for an unstable 3D slip surface growth in both convex and concave slopes are proposed and validated by fitting numerical results for various sizes and aspect ratios of the initially pre-softened zone.
On the use of seashells as green solution to mechanically stabilise dredged sediments
Petti, Rossella; Vitone, Claudia; Marchi, Maurizio Iler; et al. (2024)
E3S Web of Conferences
The article reports the results of an experimental activity conducted on dredged fine-grained marine sediments and aimed to find out novel eco-friendly solutions for their mechanical stabilisation. The main idea of this research is to use seashells, i.e., another waste material, to partially replace cement binders in the mechanical stabilisation of sediments for the production of a new stable material that can potentially be used in construction. To this aim, an original procedure has been developed to obtain a powder of mussel shells without their calcination. Physical properties, one-dimensional compression behaviour and permeability of the novel mixtures including sediments, mussel shell powder and cements are presented for different curing times. The efficacy of the solutions is assessed also by comparison with the performance of control mixtures prepared by mixing the same sediments with cement only. The effects of the different treatments on the soil properties were analysed, demonstrating multiple beneficial effects of using the mussel shell powder. Evidence is provided that seashells represent a viable alternative to cement, as they were found to be as effective as traditional hydraulic binders, when replacing them up to ¼, in enhance geomechanical and geochemical performance of the stabilised material.
Basin Sediments Geometry and Strength as Controls for Post-Failure Emplacement Style of Alpine Sub-Lacustrine Landslides
Klein, Boaz; Puzrin, Alexander; Stoecklin, Andreas; et al. (2022)
Journal of Geophysical Research: Solid Earth
Predicting the evolution of underwater mass movements in their post-failure stage is vital for risk assessment of offshore structures and ensuring safety of coastal communities threatened by tsunami waves. In the absence of sedimentological and geotechnical data, variability of the post-failure behavior in a specific marine or lacustrine setting is often attributed to predisposition factors such as the slope height-drop and depth to the basal shear surface. In this paper, the contribution of other geometrical parameters such as the slope inclination and the relative thickness of the frontal basin sediments is investigated using a coupled Eulerian-Lagrangian finite element framework. An emphasis is given to the important role of the strength difference between the slope and frontal basin sediments. The suggested framework is first validated against the well-documented Zinnen slide in Lake Lucerne (Switzerland), successfully reproducing the post-failure geometry and capturing the main features observed in published seismic profiles. It is then applied in a parametric study to illustrate the decisive role of the frontal basin sediments in determining the post-failure geometry of underwater mass wasting in similar settings.
A MPM framework for large deformation seismic response analysis
Kohler, Marc; Stoecklin, Andreas; Puzrin, Alexander (2022)
Canadian Geotechnical Journal
Landslides are often triggered by earthquakes and can cause immense damage due to large mass movements. To model such large-deformation events, the material point method (MPM) has become increasingly popular in recent years. A limitation of existing MPM implementations is the lack of appropriate boundary conditions to perform seismic response analysis of slopes. In this article, an extension to the basic MPM framework is proposed for simulating the seismic triggering and subsequent collapse of slopes within a single analysis step. Original implementations of a compliant base boundary and free-field boundary conditions in the MPM framework are presented, enabling the application of input ground motions while accounting for the absorption of outgoing waves and the free-ground movement at the lateral boundaries. An example slope is analysed to illustrate the proposed procedure and to benchmark it against the results obtained using an independent simulation technique, based on a three-step FE analysis. The comparison generally shows a good agreement of the results obtained from the two independent procedures and highlights advantages of the presented “all-in-one” MPM approach, in particular for long duration strong motions.
Distributed Fiber Optics Measurements of Rock Deformation and Failure in Triaxial Tests
Vasquez, Antonio Salazar; Rabaiotti, Carlo; Germanovich, Leonid N.; et al. (2022)
Journal of Geophysical Research: Solid Earth
The implementation of distributed strain measurement methods in triaxial and uniaxial tests have demonstrated the development of strain localization, even at early stages. This implies that single point measurement methods are location dependent. The use of distributed methods is required not only to improve the interpreted constitutive parameters obtained from triaxial tests, but also to understand the implications of strain localization in the failure process. This work uses optical fibers in triaxial tests. The developed distributed measurement method was implemented on granite, gabbro, and sandstone samples and tested under different confining pressures, reaching 200 MPa on the granite sample. Using a temporal resolution of 0.25 Hz and 5 mm of spatial resolution, the strain evolution at over 300 locations at the sample surface was measured during testing. When compared to point sensing methods, the use of optical fiber greatly increases the number of measurements at the surface of the sample, and their interpolation provides the entire deformation of the sample surface. In all the tests performed, strain localizations were revealed before failure. A three-dimensional interpretation of a test, combining an optical scan of the sample and the distributed measurements, show good correlation between the fractures and the strain localization.
Use of shells for the mechanical stabilisation of sediments: a valuable geomechanical perspective?
Petti, Rossella; Vitone, Claudia; Marchi, Maurizio Iler; et al. (2024)
Géotechnique
The present study contributes to develop a novel eco-friendly solution for the mechanical stabilisation of dredged marine sediments by using mussel shells, i.e., another highly impacting waste of marine origin, in partial replacement of cements. Which are the underlying chemo-mechanical interactions affecting the evolution of such mixtures? Can the mussel shells replace cement without compromising useful geomechanical and geochemical properties of the stabilized sediments? Can such mixtures still be modelled as soils when it comes to their geotechnical design and analysis? The paper answers these questions by assessing the mechanical performance of the mixtures formed by sediments stabilised with three types of cement and a mussel shell powder and comparing it with that of the same sediments when treated with cement only. Multiple beneficial effects of the use of mussel shell powder, as peculiar source of calcium carbonate for its biogenic origin, have been demonstrated: it acts as a void filler, enhances the electrolytic exchanges between sediment and cement, and increases the contact area between the mineral particles promoting the chemical hydration reactions. As a result, for fixed replacement ratios, the original mixtures still exhibit soil-like behaviour consistent with traditional geomechanics and even better performances than the control mixtures.
Depth integrated modelling of submarine landslide evolution
Zhang, Wangcheng; Puzrin, Alexander (2021)
Landslides
Submarine landslides are a major geohazard among worldwide continental slopes, posing significant threats to offshore infrastructure, marine animal habitats and coastal urban centres. This study establishes an original numerical package for time-efficient modelling of the entire submarine landslide evolution covering the pre-failure shear band propagation, slab failure and post-failure dynamics. The numerical scheme is based on the conservation of mass and the conservation of momentum and combines the shear band propagation theory and the depth-integrated method, with the consideration of the drag force from the ambient water. Shear band propagation in the weak layer and slab failure in the sliding layer are controlled by the strain softening and rate dependency of the corresponding undrained strength parameters. The post-failure behaviour in the sliding layer, such as retrogression upslope and frontally confined and frontally emergent mechanisms downslope, is also simulated. The numerical results from the proposed method are comparable to the analytical solutions and the large deformation finite element analysis. Application of this method to a back analysis of the St. Niklausen slide in Lake Lucerne reproduced the observed shape of the mass transport deposits, the position of the main scar and the travel distance. Because of its easy implementation and efficiency, the proposed numerical method for modelling of submarine landslides seems promising for practical applications.

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Alexander Puzrin

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