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Illustrative diagram of the slope models: (a) Slope A with a deep soil cover and (b) Slope B with a shallow soil cover.
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In this paper, a new fully-coupled Smoothed Particle Hydrodynamics (SPH) formulation for unsaturated soils is developed to study the influence of rainfall infiltration on slope stability. The single-layer two-phase formulation is investigated in SPH for the first time to simulate the response of unsaturated soils. The use of a single set of particl...
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A simplified technique for the enforcement of boundary conditions along solid profiles is proposed in the framework of the Smoothed Particle Hydrodynamics. The main idea relies on a local definition of the normal and tangent vectors to the solid body, along with a local mirroring of the flow fields. This compound approach allows for a robust and ac...
The Smoothed Particle Hydrodynamics (SPH) method with the unified semi-analytical wall boundary conditions is used to simulate a novel approach for free-surface wave pumping inspired from Libeau impedance pump: Resonance wave pumping. The results are compared to experimental data. Using the rule of thumb numerical parameters for the weakly in-compr...
Lateral spreading due to earthquake induced soil liquefaction is frequently observed, but the resulting deformation is usually limited within several meters in near level ground. However, lateral spreading of several hundred meters was observed in very gentle slope ground within 0-3° in Balaroa during the 2018 Sulawesi Earthquake. In this study, nu...
High altitude relight is a matter of increasing importance for aero engine manufacturers, in which combustion plays literally a vital role. In this paper we want to evaluate the predictive capability of a combined Smoothed Particle Hydrodynamics (SPH) and Large Eddy Simulation with Conditional Moment Closure (LES-CMC) approach for a spray combustio...
Citations
... The smoothed particle hydrodynamics (SPH) (Gingold and Monaghan, 1977;Lucy, 1977), a fully Lagrangian particle-based method, is inherently ideal for tackling simulations involving significant deformations, particularly when dealing with material fracture and failure (Peng et al., 2017;Feng et al., 2022). Compared with traditional gridbased methods such as the finite element method (FEM), the SPH method eliminates the concern of decreased computational precision caused by grid distortion with significant deformations. ...
A new smoothed particle hydrodynamic (SPH) method is developed based on a low-dissipation Riemann solver to model the large deformation of granular materials with reduced numerical dissipation to improve the calculation accuracy. Numerical dissipation can be controlled precisely by the limiter in the Riemann solver and a stress diffusion term is adopted to remove the spurious stress profile. The design of our algorithm framework can be applied for both two-dimensional (2D) and three-dimensional (3D) scenarios, and 2D/3D simulations for granular flows are conducted for validation. The numerical results from this study are compared with experimental data from both qualitative and quantitative perspectives, demonstrating a satisfactory agreement and convergence with experimental results. Furthermore, its application on granular flows interactions with rigid barriers and natural terrain is explored and computational efficiency is also investigated. The proposed algorithm is implemented in an open-source library for further comparison and in-depth study.
... Smooth particle hydrodynamics (SPH) 12,13 is a widely-used meshless particle method which uses the kernel function for the point-based interpolation and is based on strong form collocation method. SPH is easy to implement and is able to model extremely large deformations, and thus has been applied in various engineering fields, such as simulating the slope failure in geomechanics, 14 the ballistic penetration of armors in defense technology 15 the dynamic response of soft tissue in medical applications, 16 and so forth. Despite its strength in large deformation simulations, SPH suffers from the tension instability meaning that, the motion of particles may be unstable under tension, and, as a result, the nonphysical particle aggregation and dispersion may occur. ...
... In order to transform Equation (14) in to the current configuration, the following pushing forward correlations 39 are employed as the Cauchy stress tensor = J −1 PF T , the current infinitesimal volume dΩ = JdΩ 0 , the current traction vector tdΓ = TdΓ 0 , the current body force vector b = J −1 B and the current gradient of the test function grad u = Grad uF −1 . By substituting above correlations, the updated Lagrangian version of Equation (14) is derived as, ...
Engineering structures may undergo large deformations, but simulating is still challenging for existing numerical methods, for example, the element‐based methods struggle from the mesh distortion and the strong form particle‐based methods exhibit tensile instability. This article aims on presenting a novel numerical method for large deformation simulations, which is named the implicit Updated Lagrangian Fragile Points Method (ULFPM). The point‐based nature of the proposed method ensures immunity to mesh distortion, and its stability is guaranteed by its foundation on weak form formulations. For verifications, the proposed implicit ULFPM has been applied to several large deformation problems. For all the examples, the proposed method is able to provide reliable results with a good agreement with the reference results. Moreover, the implicit ULFPM performs better than the Finite Element Method to some extent for extremely large deformation problems. It is also discussed that the accuracy of the implicit ULFPM is improved significantly by using the support domain refinement scheme. The examples indicate that the proposed method can serve as a reliable tool for predicting the large deformations of structures in engineering practices.
... The ability of the SPH to fully resolve both solid and fluid phases allow it to capture complex water-soil two-phase processes within a unified method. Recently, SPH has been used to model twophase phenomena relevant to soil piping failure (Bui et al., 2022;Feng et al., 2022;Peng et al., 2017;Zhu et al., 2022), submarine landslides (Manenti et al., 2012;Shi et al., 2016) and subaqueous sediment scouring (Fourtakas and Rogers, 2016;Zubeldia et al., 2018). In these SPH models soil erosion, soil-water mixing, and soil deposition are simplified (e.g., Han et al., 2020) and the re-erosion of the deposited soils with weak resistance are not considered (Haas et al., 2020), despite being key processes in overtopping dam breaching failure. ...
Erosion and deposition induced by overtopping flow strongly impacts the breaching evolution of landslide dams. However, these two processes are not yet sufficiently captured in current dam breaching models. In this paper, we simulate the Erosion and Deposition process during overtopping dam breaching using a novel Smooth Particle Hydrodynamics (ED-SPH) method. A new multi-function boundary is proposed to prevent the penetration of water and soil particles and ensure steady inflows. Dam break and movable erosion scenarios are simulated as a means to validate the model. Dam breach simulations using the ED-SPH method reveal that the proposed model can capture the complex dam soil erosion, entrainment, and depositions behaviors. The soil deposition hinders the eroded particle movement and reduces the water velocity at the water-soil interface. If soil deposition is not considered, as in many existing models, the breaching time decreases and the outburst flood discharge is magnified. We further investigate the re-erosion of deposited soils by varying the re-erosion coefficient. With decreasing the re-erosion coefficient, the peak discharge increases whereas the residual dam height decreases due to the blockage by the deposited soils.
... More recently, Morikawa and Asai [12] applied the incompressible smoothed particle hydrodynamics (ISPH) projection method to solve coupled soil-water interaction in saturated soil using the u-w-p Biot's formulation (w denotes seepage discharge). Feng et al. [13] proposed a single-layer two-phase SPH model for saturated/unsaturated soils based on a similar u-w-p formulation but with the weakly compressible assumption. It was shown that their model enables the analysis of slope failure under extreme rainfall events with a noise-free stress field. ...
... This paper develops a general SPH framework for coupled flow-deformation problems in porous materials. The new framework is built upon the SPH formulations proposed by Feng et al. [13]. Several enhancements are introduced to improve the accuracy and stability of the numerical solution, and to extend the applicability to complex hydro-mechanical scenarios. ...
... To solve the continuum mixture model in a Lagrangian mesh-free method, the single-layer approach is adopted due to its efficiency in computation as well as boundary treatment [13,14]. In this approach, only a single set of particles is adopted to describe the physical domain of concern, and the governing equations of each phase are solved within each individual particle. ...
The method of smoothed particle hydrodynamics (SPH) has been recently developed to study the coupled flow-deformation problems in porous material and considerable success has been achieved comparing to traditional mesh-based method, especially for treating large deformation and post-failure. However, computational challenges remain for the hydro-mechanical boundary treatment as well as the accuracy and stability of the numerical scheme. It is shown that the use of conventional SPH operator for the solution of the coupled problem can lead to several issues including numerical instabilities, inaccuracies and unphysical particle clumping as well as particle disorders near the boundary. To address these issues, a general SPH scheme with enhanced accuracy for saturated/unsaturated porous material is proposed in this paper. An improved SPH formulation for seepage analysis is proposed to allow an accurate prediction of liquid flow in porous material. A new stabilisation technique that combines the use of a density diffusion term, a modified particle shifting algorithm, and a new viscous damping term is developed to further improve the accuracy, stability and robustness of the proposed method. The implementations of stress boundary conditions and hydraulic boundary conditions in SPH, such as confining stress, hydraulic head, infiltration/evaporation, and potential seepage face, using either wall boundary particles or free-surface domain particles, are discussed in detail. A range of benchmark examples is adopted to verify the validity of the present coupled framework. The proposed model is finally applied to simulate the failure process of embankment dam due to rapid drawdown. Results indicate that the methodology proposed herein can be a promising tool for the analysis of the coupled hydro-mechanical process in porous material involving large deformations.
... Additionally, these studies often simulate the instantaneous impact of homogeneous landslide bodies on underwater structures (Zakeri et al. 2009;Nian et al. 2018;Guo et al. 2021), neglecting the morphological evolution of the landslide's leading edge during the pre-impact transportation process, which makes it deviates from the actual morphology of offshore landslides. In recent years, meshless methods, such as Smoothed Particle Hydrodynamics (SPH), have gained increasing popularity in geotechnical engineering studies (Dai et al. 2017;Zhang et al. 2019;Feng et al. 2022). The SPH method offers significant advantages in simulating the discontinuous deformation and largedeformation flow of soils (Chen and Yan 2021), as it does not rely on the assumption of macroscopic continuum media. ...
Background
As the exploitation of marine resources intensifies, the impact of submarine landslides on underwater structures has become a significant issue. Existing research primarily focuses on the impact on pipelines, often neglecting the actual deformation and mechanical response of underwater structures under impact loads in numerical simulations, thus complicating the evaluation of the reliability of these engineering structures in extreme conditions. Moreover, the dynamic response of bucket foundations, a common form of underwater base, under the effect of submarine landslide impacts remains unclear.
Methods
To address this knowledge gap, we have developed a fluid-structure coupling system that employs the coupled Smoothed Particle Hydrodynamics (SPH)-Finite Element Method (FEM) to investigate a single impact process and analyze the displacement response of bucket foundations within a water-offshore landslide-bucket foundationsubgrade context. The accuracy of this developed method has been systematically verified through comparisons with previous experimental and numerical results.
Results
During a submarine landslide impact event, the impact force demonstrates a distinct decrease followed by stabilization, and the displacement response of the bucket foundation exhibits a rebound effect after reaching its maximum value. Furthermore, we conducted an extensive analysis of different impact angles for underwater data centers equipped with multi-bucket foundations. Our study revealed that group-bucket foundations experience a combined translation-turnover failure when subjected to submarine landslide impacts, and the most unfavorable scenario for such impact is identified. The research introduces a novel numerical simulation approach for investigating the impact of submarine landslides on complex underwater structures.
... The Bingham model was used to describe its movement process, and the dilatancy behavior during the movement of the landslide body was ignored. In comparison with the boundary conditions of contact solid boundary condition [33], the dynamic solid boundary can mitigate boundary particle defects, and in comparison with the symmetric virtual particle boundary condition, the dynamic solid boundary has an advantage in building complex boundary [34]. The flume was described by the dynamic boundary conditions. ...
Landslides blocking rivers in alpine canyon areas can cause great harm. Taking the Bageduzhai landslide on the southeastern margin of the Qinghai-Tibet Plateau as an example, the risk of landslides blocking rivers is analyzed by static analysis and dynamic simulation. Through onsite investigation, it is found that the Bageduzhai landslide is a traction-falling landslide, and there are two sliding surfaces: deep and shallow. Through static analysis of the stability of the Bageduzhai landslide under ordinary rainfall conditions and high-intensity rainfall conditions, the sliding surface position is obtained. On this basis, the smooth particle hydrodynamics method is used to analyze the movement process and accumulation form of the landslide under different working conditions. The analysis results show that the instability volume and sliding surface depth of the landslide under ordinary rainfall conditions are significantly smaller than those under high-intensity rainfall conditions. The instability volume and sliding surface depth under ordinary rainfall conditions can reach 31 m. The river-blocking depth under extreme rainfall conditions can exceed 65 m. The research results provide theoretical support for the risk analysis of the potential river-blocking disaster of the Bageduzhai landslide.
... Zhang et al. (2016Zhang et al. ( , 2019 proposed and validated a two-phase coupled SPH model through the simulation of a dike failure test and conducting stability analysis of a soil slope. Feng et al. (2022) presented a new fully-coupled SPH formulation for unsaturated soils, which investigates the influence of rainfall infiltration on slope stability and allows for the simulation of both triggering and post-failure mechanisms. These studies demonstrate the usefulness and efficiency of SPH in geotechnical and geological engineering applications, and highlight its ability to simulate a range of phenomena including slope stability, rainfall infiltration, and post-failure mechanisms. ...
This work presents an improved soil‒water coupling model to simulate landslide‐generated impulse waves (LGIWs) in a unified smoothed particle hydrodynamics (SPH) framework, where both water flow and landslide motions are modeled by SPH using an interface coupling technique. Graphics processing unit technology based on an open‐source platform DualSPHysics is chosen to employ the landslide dynamics and soil‒water interface coupling to achieve the capability of large‐scale simulation and high‐resolution modeling for three‐dimensional LGIW problems. A subaerial landslide‐generated water waves, is simulated to demonstrate the accuracy and ability of this model. The Huangtian LGIW is then simulated to reproduce the entire disaster chain, including landslide dynamics, fluid‒solid interaction, and surge wave generation. Particle resolution dependence is examined, giving a particle distance of 5.0 m, which can provide a converged landslide deposit and surge wave. The simulation shows that in the Huangtian LGIW, the landslide deposit volume was approximately 41.6 million m³ (600 m width, 768 m length, and 400 m above the still water level), with an immersed landslide volume of 11.3 million m³; for the surge wave, the maximum wave and run‐up heights were 34.3 and 48 m, respectively. These results are within the estimated ranges of both the landslide and surge wave according to limited field survey data. The case study of the Huangtian LGIW provides a typical reference of how to reproduce a reliable whole process of large scale multi‐physical and multiscale LGIW, including full information of landslide dynamics, interface coupling behavior, and surge wave characteristics.
... SPH is a powerful particle-based numerical method whose meshfree nature makes it suitable to simulate multiphysics problems involving extreme deformations, material separation, and free-surface flows, and is thus ideal for the classes of problems considered in the present effort. Several different versions of SPH have been developed throughout the years, and many challenging problems have been solved, and the interested reader should review [3,[47][48][49][50][51][52][53][54][55][56][57], and the included references. In the present effort, the weakly compressible SPH (WCSPH) [49] is employed for the fluid dynamics subproblem, and is supplemented with a turbulence model to handle the turbulent nature of extreme hydrodynamic events. ...
We present a proof-of-concept particle-based fluid–structure interaction (FSI) computational framework for modeling structural fracture and fragmentation under the impact of extreme hydrodynamic events. The smoothed particle hydrodynamics (SPH) approach is employed to discretize the equations of motion for both the fluid and structural domains. The meshfree nature of the discretization technique accommodates the simulation of scenarios involving extreme structural deformations and material separation, as well as free-surface flows. The framework is supplemented with a phase-field model of brittle fracture that allows for the simulation of crack nucleation, propagation, and branching, which leads to realistic modeling of structural responses during extreme hydrodynamic events. In the end, a novel algorithm for coupling the fluid and solid subproblems is presented. The proposed approach is verified and validated against existing computational methods and experimental results, and in the end, a few challenging problems involving complex fracture patterns and fragmentation are presented.
Graphical abstract
... The mechanical properties of unsaturated soil closely depend on the humidity characteristics [2,3]. The dependence of mechanical behaviors on matric suction or moisture involved in many engineering problems has been reported on in studies of foundation engineering, subgrade engineering, and slope engineering [4][5][6][7][8]. For example, after the soft soil humidifying, the stiffness of the soil subgrades decreased evidently, resulting in the settlement and collapse of the pavement structure. ...
Unsaturated soil is a form of natural soil whose pores are filled by air and water. Different from saturated soil, the microstructure of unsaturated soil consists of three phases, namely, the solid phase (soil particle), vapor phase, and liquid phase. Due to the matric suction of soil pores, the hydraulic and mechanical behaviors of unsaturated soils present a significant dependence on the moisture condition, which usually results in a series of unpredictable risks, including foundation settlement, landslide, and dam collapse. Microbial-induced calcite precipitation (MICP) is a novel and environmentally friendly technology that can improve the water stability of unsaturated soft or expansive soils. This paper reviews the microscopic mechanisms of MICP and its effect on the mechanical properties of unsaturated soils. The MICP process is mainly affected by the concentration of calcium ions and urea, apart from the concentration of bacteria. The moisture-dependent properties were comparatively analyzed through mechanical models and influence factors on the experimental data among various unsaturated soils. It suggests that the variations in resilient modulus and permanent deformation are strongly related to the extent of MICP applied on unsaturated soils. Finally, the problems in the MICP application, environmental challenges, and further research directions are suggested.
