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The volume of a submarine landslide is likely to be amplified by shear band propagation along a basal surface or spreading failure extension in the sliding layer. Although the mechanism of translational submarine landslides has been understood using the interpretation of shear band propagation, assessment of the limits of failure extension, either...
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... A submarine landslide is a common geological hazard that occurs on the continental shelf and is susceptible to crust-tectonic activity, earthquake effects, or rapid sedimentation [1][2][3][4][5][6][7][8][9][10]. These landslides are characterized by their large volume, high velocity, and runout distances. ...
... Equation(6) instead of the total sediment layer height, H. The observed trend suggests that the utilization of the proposed discretization approach leads to a decrease in excess pore pressure results due to an artificial extension of the drainage path. ...
Rapid sedimentation is widely recognized as a crucial factor in initiating the instability of submarine slopes. Once the slope fails, the subsequent landslide poses a significant threat to the safety of underwater infrastructures and potentially leads to severe damage to seabed pipelines, offshore foundations, and oil and gas exploitation wells. However, there is currently a lack of numerical methods to effectively assess the real-time stability of submarine slopes under rapid sedimentation. This study firstly employs a calibrated finite element (FE) model-change approach to reproduce the rapid sedimentation processes and proposes a concise method to calculate the safety factors for the real-time stability of sedimenting submarine slopes. Further, a parametric analysis is carried out to evaluate the effect of varying sedimentation rates on slope stability, and the critical sedimentation rate is numerically solved. Moreover, the effect of seismic events with different occurring times on the stability of rapidly sedimenting slopes is investigated in depth, and the most critical seismic loading pattern among various acceleration combinations is achieved. The results indicate that the presence of weak layers during sedimentation is a critical factor contributing to slope instability. The introduced rate of decrease in the safety factor proves valuable in assessing slope safety over a specific period. As the occurrence time of seismic events is delayed, the seismic resistance of the slope decreases, increasing the likelihood of shallower sliding surfaces. The findings offer insights into the mechanisms by which rapid sedimentation influences the stability of submarine slopes and provide valuable insights for predicting the potential instability of rapidly sedimenting slopes under specific seismic activity levels.
... For a particulate system, however, such as an earth dam composed of strain-softening iron ore tailings, it manifests itself as a slip surface growth, which can be either progressive (steady-state), requiring increasing external loads, or catastrophic (unstable), under existing external loads [28][29][30][31][32] . At a certain limit, progressive slip surface growth can evolve into the catastrophic failure, the criteria for which have been discussed in Zhang et al. 33 . ...
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.
... Propagating glide planes can eventually disrupt the overlying strata to form local fractures and slabs on the upper continental slope (Laberg et al., 2013;Zhang et al., 2021). These slabs can then be softened, fractured, and fragmented by high dip-angle fractures, ending up as a series of laterally spread blocks on a gentle submarine slope (Micallef et al., 2007;Baeten et al., 2014;Wu et al., 2021). ...
... Failed slabs are large and irregular, but maintain a coherent inner structure until they are fragmented into series of blocks during their downslope transport (Micallef et al., 2007;Dey et al., 2016). Numerical simulations further suggest that, during the fragmentation of moving slabs, blocks can spread from both their lower and upper boundaries (Debnath, 2018;Zhang et al., 2021). ...
... Laterally spread blocks generated from the lower boundary of a slab may also form retrogressively as they use a fully evacuated lower slope to accommodate their movement (Alves, 2015;Zhang et al., 2021) (see the "retrogressive model" in Fig. 10D). Laterally spread blocks detached from the upper boundary of a slab develop progressively and are partially supported by the moving slab, limiting their transport (Dong et al., 2017;Debnath, 2018;Zhang et al., 2021) (see the "progressive model" in Fig. 10E). ...
Submarine landslides are significant geohazards, capable of displacing large volumes of sediment from continental margins to deposit mass transport complexes (MTCs) and generate offshore tsunamis. However, the reactivation of MTCs after their initial failure has long been overlooked. By analyzing high-quality three-dimensional seismic reflection data and seismic attribute maps, as well as comparing the geometry of different MTCs, we investigate the development of long-term slope instability and its hazardous consequences on the northwest flank of the Storegga Slide on the Norwegian margin. Our results demonstrate that the reactivation of MTCs can deform both their inner structure and overlying strata, promoting the formation of sinuous channels and local slope failures on the seafloor. These findings further reveal the MTCs that are underconsolidated or comprise slide blocks may remain unstable for a long time after their initial failure, particularly when affected by slope undercutting and a corresponding reduction in lateral support. This study shows that MTC-prone sequences are more likely to comprise regions of continental slopes with long-term instability and recurring marine geohazards.
... B = 8 m), a large triangle block is formed close to the right end of the domain. Such a triangular block failure pattern has also been reported in (Locat et al., 2017(Locat et al., , 2011 and numerically reproduced in (Dey et al., 2016;Wang et al., 2021a;Zhang et al., 2021;Zhang et al., 2020). Our simulation indicates that the loading type also affects the failure mode in sensitive clays. ...
This paper presents the nodal integration-based particle finite element method (N-PFEM) for poro-elastoplastic analysis of saturated soils subject to large deformation, utilising the generalised Hellinger-Reissner variational principle to reformulate the governing equations for saturated soil dynamics into a min-max optimisation problem. With finite element discretisation and nodal integration over cells, the problem is transformed into a standard second-order cone programming problem, efficiently resolved using the advanced primal-dual interior point method. The N-PFEM method has several advantages, including the use of linear triangular elements without volumetric locking issues, the avoidance of regularisation techniques, and the elimination of tedious variable mapping after remeshing. The numerical model is validated for large deformation analysis of saturated soils with a series of benchmarks against available analytical and numerical solutions, with a case study of the deformation of an embankment considering stone column reinforcement also carried out. This N-PFEM framework offers an effective and efficient simulation approach for the evolutionary behaviour of saturated soils with large deformation in complex geotechnical configurations of practical relevance.
... 22 Over the years, a considerable amount of work has been devoted to the understanding of these mechanisms and the estimation of their potential dimensions. Among the methods used were analytical energy-based criteria 20,23-26 and limit equilibrium [27][28][29] and various numerical methods such as large deformation finite element analysis, 28,30-32 material point method, 33,34 smooth particle hydrodynamics, 35 particle finite element method, 36 depth-integrated methods [37][38][39][40][41][42] and more. ...
... Firstly, the relevant theory required to estimate failure initiation dimensions of the failed slab is presented. Secondly, the analytical criterion of Zhang et al. 28 is implemented for determining the retrogression limit above this slab. Finally, a newly developed depth-integrated finite element method (DIFEM) with adaptive remeshing is developed to simulate the landslide evolution and to assess its downslope extent. ...
... wherē= 0 is the average shear stress ratio in the interval ∈ {0, = 0 } and̂= 0 = =0 ∕ . The necessary condition for retrogressive failure 28 becomes ...
Stability analysis of submarine and sublacustrine slopes requires special attention to the strain-softening nature of clay-rich sediments. Utilizing the often-used infinite slope assumption using the peak strength is inadequate for the task at hand as the well-known limit equilibrium method may provide non-conservative estimate of marine slopes’ stability. In this paper, a GIS based framework is developed to account for a more suitable shear band propagation slope-failure criterion for basin-wide stability calculations. After determining the slab failure prone areas, the framework employs analytical criterion for retrogressive failure above the slab and depth-integrated finite element method for calculating the size of confined slides at the toe. This allows predicting the landslide’s post-failure configuration and the overall landslide coverage zone. The framework is first benchmarked to prove its competence and then applied to the well documented Zinnen Slide and the southeastern banks of the Küssnacht Basin, Lake Lucerne, Switzerland. The results of the application show good agreement with the observed basin geomorphology.
... In order to accurately determine the cascading failure, the interdependence and degree between nodes in the system have become a new research point. Aiming at this problem, some of the literature has studied it [4,9,[11][12][13]. Koosha Marashi et al. [4] used correlation measures and heuristic causal analysis to identify the interdependence between components of network physical systems. ...
... The laboratory tests under long-term hydro-mechanical coupling were carried out based on the cement mortar specimen containing adjacent preexisting cracks, and the microcrack evolution in the specimen was analyzed by using lowfrequency nuclear magnetic resonance technology, the corresponding numerical simulation was carried out to study the propagation and interaction behavior of adjacent cracks and the time-dependent mechanism of creep failure of rocks [12]. Zhang et al. [13] explored the possibility of all failures and quantifies the initiation and extension of failures accordingly. ...
... Wang Pengjun et al. [22] studied the application of the equipment-status-assessment method based on deep learning in PHM scenarios. After understanding the process of failure propagation, it is also very important to calculate the failure propagation probability to ensure the safe operation of the system [1,8,13,18,20,21]. ...
Interdependence is an inherent feature of the cyber-physical system. Small damage to one component in the system may affect several other components, leading to a series of failures, thus collapsing the entire system. Therefore, the system failure is often caused by the failure of one or more components. In order to solve this problem, this paper focuses on a failure propagation probability prediction method for complex electromechanical systems, considering component states and dependencies between components. Firstly, the key component set in the system is determined based on the reliability measure. Considering the three coupling mechanisms of mechanical, electrical, and information, a topology network model of the system is constructed. Secondly, based on the topology network model and fault data, the calculation method of influence degree between components is proposed. Three state parameters are used to express the risk point state of each component in the system through mathematical representation, and the correlation coefficient between the risk point state parameters is calculated and measured based on the uncertainty evaluation. Then, the influence matrix between the system risk points is constructed, and the fault sequence is predicted by using the prediction function of an Artificial Neural Network (ANN) to obtain the fault propagation probability. Finally, the method is applied to the rail train braking system, which verifies that the proposed method is feasible and effective.
... Retrogressive landslides are geohazards that often occur in sensitive clay areas (Quinn et al. 2012;Locat et al. 2013;Puzrin et al. 2017;Richer et al. 2020;Zhang and Wang 2020;Zhang et al. 2021). A unique characteristic of retrogressive landslides is that an initial small local slope failure may cause a catastrophic landslide proceeding abruptly in a retrogressive manner and finally eroding apparently stable areas that are far away from the initial small local failure (Zhang et al. 2019). ...
... A variety of numerical approaches were developed to reproduce the complete process of spreading landslides and analyze the failure mechanism as well as propagation of retrogressive landslides, such as coupled Eulerian-Lagrangian (CEL) method (Dey et al. 2015(Dey et al. , 2016a(Dey et al. , 2016bStoecklin et al. 2021), the material point method (MPM) (Wang et al. 2016;Dong et al. 2017;Tran and Solowski 2019;Cuomo et al. 2021aCuomo et al. , 2021b, the particle finite element method (Zhang et al. 2017(Zhang et al. , 2018(Zhang et al. , 2019, and the large deformation finite element method (Wang et al. 2013;Shan et al. 2021;Zhang et al. 2021). A few key characteristics in spreading failure were captured in those works including the initiation and propagation of retrogressive failure, multiple progressive failures, and formation of horsts and grabens, which demonstrates that numerical simulation is a very promising tool to reveal the failure mechanism of spreads. ...
Spreading landslides are geohazards that often occur in sensitive clay areas. A unique characteristic of the spreads is that an initial small local slope failure may cause a catastrophic landslide above the horizontal failure surface, forming horsts and grabens. Although many hypotheses were proposed to explain the failure mechanism of spreads, some topography of the landslides observed from field investigations cannot be well explained by the existing hypotheses. This study revisits the 2010 Saint-Jude spreading landslide by using the coupled Eulerian–Lagrangian approach within ABAQUS to reveal the failure mechanism of spreading landslides. Two types of cross-sections (static and dynamic cross-sections) were selected to monitor the total horizontal force of the sliding mass during the process of migration. It was found that there are two spreading failure mechanisms to form horsts and grabens. The first one is the static spread failure mechanism that global failure occurs accompanied by spreading failure. The other one is the dynamic spreading failure mechanism that after the global failure, the sliding masses break into horsts and grabens during the forward movement under the pushing of the sliding mass at the back and the blocking action of the soil mass in the front. These two failure mechanisms of spreads can well explain various geomorphologic shapes found in the Saint-Jude landslide.
... For instance, Puzrin et al. 32 has established a criterion for the further upslope failure in submarine spreads, in which the concept of critical drop height of the failed block was proposed as an important parameter. Zhang et al. 33 further developed the critical drop height of the failed block and applied it to the curvilinear submarine slopes. Ordinarily, the failed blocks in submarine landslides triggered by earthquakes could travel a long distance before their final deposition. ...
... 23,39,40 Subsequently, this method was extended to illustrate the retrogressive failure caused by foot unloading combined with the active block failure of the sliding layer. 32,41 More recently, Zhang et al. 33 developed a series of criteria to assess various failure scenarios and retrogression distances in submarine slopes under the assumptions of a spread failure pattern. In the present study, the failure pattern is an open issue and will be discussed by searching for the shape function of the most critical failure surface. ...
... The peak strength is mobilized at = 0 (̂=̂0), and the division point between the residual and the process zones is located at = 1 (̂=̂1). As in the studies by Zhang et al. 23,33 the zone located between = 0 and = 0 on the basal surface is defined as the shear band with | 0 | representing its length. ...
The failure patterns and retrogression distances in sensitive clays induced by river erosion are two significant factors of concern in landslide risk assessment. For the former, empirical criteria, based on past events and numerical results, can hardly produce a unified guideline and explain their complex mechanism. For the latter, the capacity of the river cross section is rarely considered in existing studies, even though the failed soil would deposit on the riverbed and further affect upslope failure extension. The present study proposes an analytical method to quantitatively assess the failure patterns and retrogression distance by combining the shear band propagation method (SBP) with limit analysis on active block failure. A closed‐form active earth pressure (CAEP) and the shape function of the failure surface are proposed with the variational calculus method (VCM), providing a tool to understand the transformation mechanism of the failure patterns. The criteria for initiation failure positions and stages are formulated following the competition results between the induced minimum slope‐parallel force by foot unloading and the proposed CAEP. Further, the terminal retrogression distance is given considering two possible river cross sections. The proposed CAEP solution is validated against Buss's solution and further applied to a parametric study on the failure patterns. Finally, three practical cases are analyzed with the proposed method, and the predictions are shown to agree well with the field observations.
... 3 of 21 mechanisms may be triggered. Loss of support at the head scarp may lead to retrogressive failure propagating upslope (Locat et al., 2011;L'Heureux, 2012;Zhang et al., 2021). Downslope, the sliding mass may break, detach from its foreland, emerge, and override its ramp ( Figure 1a). ...
... Studies focused on prediction of post-failure evolution often consider the sediments to be homogeneous from a geotechnical perspective, namely strength, stiffness and bulk density (e.g., Buss et al., 2019;Puzrin, 2016;Zhang et al., 2021). In a study conducted by Wilson (1970) on sediments taken from the Southern California Continental Borderland area, samples were collected from four different sedimentary environments, namely the continental shelf, the basin floor, the continental slope, and the submarine canyon fan. ...
... The second step consists of a dynamic, explicit, total stress-based coupled Eulerian-Lagrangian (CEL) analysis. This modeling technique can accommodate very large deformations without losing its accuracy due to mesh distortion as in standard Lagrangian FE analysis and has been found adequate to model similar problems, for example, Dey et al. (2015Dey et al. ( , 2016, Stoecklin, Friedli, and Puzrin (2020), Klein and Puzrin (2021), Zhang et al. (2021). Both steps are performed using the ABAQUS computing environment (Dassault Systèmes Simulia Corp., 2014). ...
Plain Language Summary
Submarine and sub‐lacustrine landslides that are sufficiently mobile to ramp out of their basal shear surface and override the seafloor over considerable distances may be responsible for tsunami waves generation. Alternatively, when confined, these landslides can still inflict significant damage on offshore infrastructure such as underwater cables breakage and destruction of offshore structures' foundation systems. To mitigate those risks, predicting the failure mechanism type and understanding its controls is crucial. In this paper, we present a finite element framework for simulating the post‐failure evolution of landslides and apply it to analyze the Zinnen landslide that took place in Lake Lucerne, central Switzerland, around the year 1601. After confirming that our framework can reproduce the observed post‐failure geometry, we use it to improve our understanding of different factors affecting the landslide dynamics and kinematics. We demonstrate, that besides the widely accepted controls such as slope height‐drop and depth to basal shear surface, other (mostly overlooked) factors may have a decisive effect on the post‐failure landslide evolution. These include the slope angle, the thickness of the frontal basin sediments and most importantly the difference in shear resistance between the slope and the frontal basin sediments.
... This induced typical grabens and ridges parallel to the headwall . From our updated bathymetric compilation, we do not observe distinct graben and ridge structures between the upper and the lower headwall, which would support the formation of these two headwalls by a retrogressive failure (Zhang et al., 2021). Retrogressive rotational slumps around the epicenter of the 1929 Grand Banks earthquake are, for example, spaced at distances between 7 and 20 km (Piper et al., 1999). ...
Submarine mega‐slides involving hundreds of cubic kilometers of slope material pose a major threat due to their potential to destroy offshore infrastructure and trigger devastating tsunamis. The Sahara Slide Complex affected about 50,000 km² of the northwestern (NW) African continental margin. Previous studies focused either on its distal depositional zone or the uppermost headwall area, but failed in reconstructing the succession of individual slide events within the entire headwall area. New hydroacoustic data reveal a complex slide morphology including three main acoustic facies, large scale slide blocks, linear troughs, multiple glide planes and three major headwall scarps (the upper, southern and lower headwall). The evacuated slide scar hosts chaotic slide deposits that cover stratified sediments in the upper and southern headwall area, but are vertically stacked onto older slide deposits in the lower headwall area. Based on these observations, and dating of recently collected sediment samples, we reconstructed the history of slope failures that led to the formation of the structurally and morphologically complex headwall area of the Sahara Slide. Slope instability initiated when the lower headwall failed at ∼60 kyr, followed by the failure of the northeastern upper headwall at ∼14 kyr. Around 6 kyr, a major slide within the upper headwall area took place, followed by a series of smaller events within the southern and most‐proximal upper headwall area. The youngest of these slides occurred around 2 kyr. This scenario suggests a long‐lasting history of successive slope failures for the Sahara Slide Complex along the NW African continental slope.
