Continuous internal erosion, commonly manifested as piping, is a major cause of failure in earthen structures. This study employs the hole erosion test to examine the internal erosion resistance of zein biopolymer–treated soil, encompassing three sandy soil types with varying particle sizes. The gelation mechanism of the zein binder is evaluated through rheological and shear wave analyses. Treated and untreated specimens are subjected to hydraulic gradients at constant flow rates. The erosion analysis focuses on changes in axial diameter, particle loss rate, shear stress, and erosion rate. The biopolymer gel demonstrates evolving rheological behaviour, transitioning from shear thickening to shear thinning after a 4-hour curing period. Treated specimens exhibit improved shear stress and erosion rate over time, which vary with particle sizes. Hydraulic shear stress decreases with the curing period, and particle size increases, correlating with erosion rate reduction. Higher consistency index of the biopolymer gel leads to decreased hydraulic shear stress, influenced by gel internal friction. Hydraulic shear stress linearly relates to shear wave velocity of the treated specimen. Zein biopolymer enhances erosion resistance of cohesionless sand through gel internal friction and treated specimen shear stiffness.

Experimental Investigations of Seepage-Induced Internal Erosion in Sand-Kaolinite Soils with Different Clay Fractions

Experimental investigation of the influence of seepage direction on internal erosion characteristics in gap-graded soils

The Laikom sacred forest, in the Boyo Highlands of Cameroon, is a critical ecological and cultural heritage site governed by centuries-old customary laws and traditional institutions. A study was carried out to assess the roles of indigenous governance, taboos, rituals, and penalties in the management of the 21.9-hectare forest, located in the environs of the Kom Palace in Laikom. Data were collected through key informant interviews and observations. The findings reveal a deeply embedded system of traditional forest governance upheld by key institutions such as the Kwifon (sacred council), Fon, sub-chiefs, traditional practitioners, and women associations (Fumbuien). Customary laws regulate agricultural practices, hunting, cleansing rituals, and forest use, often transmitted through oral traditions, community gatherings, and ceremonies. The forest’s sanctity is protected by taboos against activities such as tree felling, hunting, and unauthorized entry, particularly by women, against severe social, spiritual, and supernatural penalties. Despite the resilience of these traditional systems, Laikom faces growing challenges including encroachment, internal leadership conflicts, climate change, and erosion of cultural knowledge. Nonetheless, traditional management strategies such as community guardianship, ritual ceremonies, and agroforestry practices remain effective in conserving the forest’s biodiversity and cultural relevance. This study underscores the importance of integrating customary laws and traditional institutions into formal environmental policy frameworks. Recognizing and supporting indigenous knowledge systems can enhance biodiversity conservation and cultural preservation. Policy interventions should aim at legally recognizing sacred forests, providing capacity-building for traditional custodians, and fostering collaborative governance models that respect local cultural values while addressing modern conservation challenges.

This paper presents a comprehensive experimental study on the mix design and performance of permeable concrete for geotechnical applications, focusing on its hydraulic conductivity, durability, and filter properties. Characterized by high porosity and minimal or no fine aggregates, classical pervious concretes are effectively utilized in various civil and environmental engineering applications, including drainage systems and erosion control. This research examines the influence of the particle size distribution of aggregates on the filter properties of permeable concrete for applications in geotechnical engineering (draining piles, deep trench drains, and draining backfill). It emphasizes the importance of resistance to clogging to maintain adequate residual hydraulic conductivity and to prevent the internal erosion of soils into which permeable concrete drains are installed. The experimental results indicate that including sand in the aggregates strongly enhances the filtering capacity of pervious concrete. These findings suggest that if the mix design of permeable concrete is developed considering the grain size distribution of the base soils, the concrete will meet long-term drainage requirements (sufficient residual hydraulic conductivity), exhibit good resistance to physical clogging, provide excellent protection for the base soils against internal erosion, and contribute to the overall stability of geotechnical systems.

Abstract Levees provide critical flood protection, but are vulnerable to failure from internal erosion and piping. According to the risk assessment study performed by the US Army Corps of Engineers’, more than 20% of the levees in the United States are considered to have a very high risk of failure. Therefore, rapid noninvasive methods that can assess subsurface conditions over long distances are needed to identify the critical zones along the levees. This study evaluates electrical resistivity tomography (ERT) to characterize levee composition and detect anomalies indicative of defects arising from thin clay layers. ERT surveys were conducted on the Melvin Price reach of the Wood River Levee and compared to previously published multichannel analysis of surface wave (MASW) measurements and historical data. Longitudinal and transverse two‐dimensional (2D) ERT imaging revealed large‐scale stratigraphy related to old river channel deposits but lacked the resolution to discern fine‐scale layering details, including a discontinuous clay layer resolved in the MASW shear wave velocity profiles. This limitation is challenging because such features are critical for understanding internal erosion at the levee. Additionally, the 2D nature of ERT inversion is susceptible to bias caused by the complex three‐dimensional (3D) geometry of levee structures, which introduces artefacts that can affect the interpretation of resistivity data. These 3D effects are particularly pronounced for longitudinal lines with air on both sides of the levee or when resistivity contrasts are low. Forward modelling confirmed limitations in the ability of 2D ERT sections to resolve certain thin clay layers during inversion. However, ERT provided a rapid overview of subsurface stratification and moisture patterns; integrating with MASW, drilling data and advanced inversion methods that correct for 3D effects is recommended to improve characterization levee condition and defects. This study highlights both the potential and inherent challenges of geophysical methods for assessing critical flood protection infrastructure.

The Permian Lucaogou Formation (PLF) shale oil reservoirs in the Junggar Basin exhibit significant lithological heterogeneity, which limits the understanding of the relationship between macroscopic and microscopic reservoir characteristics, as well as insights into reservoir quality. To address this gap, thirty core samples, exhibiting typical sedimentary features, were selected from a 46 m section of the PLF for sedimentological analysis, thin section examination, high-performance microarea scanning, and scanning electron microscopy. Seven main lithofacies were identified, including massive bedding slitstone/fine-grained sandstone (LS1), cross to parallel bedding siltstone (LS2), climbing ripple laminated argillaceous siltstone (LS3), paired graded bedding argillaceous siltstone (LS4), irregular laminated argillaceous siltstone (LS5), irregular laminated silty mudstone (LM2), and horizontal laminated mudstone (LM2). The paired graded bedding sequences with internal erosion surfaces, massive bedding, and terrestrial plant fragments suggest a lacustrine hyperpycnal flow origin. The channel subfacies of hyperpycnal flow deposits, primarily consisting of LS1 and LS2, reflect strong hydrodynamic conditions, with a single-layer thickness ranging from 1.3 to 3.8 m (averaging 2.2 m) and porosity between 7.8 and 14.2% (averaging 12.5%), representing the primary sweet spot. The lobe subfacies, composed mainly of LS3, LS4, and LS5, reflect relatively strong hydrodynamic conditions, with a single-layer thickness ranging from 0.5 to 1.4 m (averaging 0.8 m) and porosity between 4.2 and 13.8% (averaging 9.6%), representing the secondary sweet spot. In conclusion, strong hydrodynamic conditions and depositional microfacies are key factors in the formation and distribution of sweet spots. The findings of this study are valuable for identifying sweet spots in the PLF and provide useful guidance for the exploration of lacustrine shale oil reservoirs in the context of hyperpycnal flow deposition globally.

Runoff and sediment yield dynamics of compound erosion between surface and pipe erosion under different slope conditions: a laboratory study

The behaviours of soil subjected to internal erosion have been widely investigated, yet the evolution of soil fabric anisotropy during erosion and the corresponding changes in post-erosion stiffness degradation curves have never been explored. This study developed a back-pressure-controlled, bender-equipped triaxial permeameter to measure the internal erosion behaviour of soils under different stress states and its consequences on the anisotropic mechanical behaviour of eroded soil. Evolutions of fabric anisotropy during erosion were evaluated by measuring the shear wave velocity at various wave propagation and polarisation directions under the isotropic loading condition. Soil samples with and without erosion were then sheared following a path of constant mean effective stress to determine the stiffness degradation curves. Results show that the losses of fines and the rearrangement of soil particles due to erosion increased the fabric anisotropy (i.e. increased horizontal alignments of soil particles) by 10% at all confining pressures. Such increase resulted in eroded specimens that were stronger than their intact counterparts upon triaxial compression, but the opposite trend was observed upon extension. The eroded specimens had a higher volumetric threshold shear strain than the intact ones, thereby suggesting that higher strains were required to substantially change the soil structure and reduce the small-strain shear stiffness.

Soil erosion affects land productivity, water quality, and ecosystem resilience. Traditional monitoring methods are often time-consuming, labor-intensive, and resource-demanding, while unmanned aerial vehicles (UAVs) provide high-resolution, near-real-time data, improving accuracy. This study conducts a bibliometric analysis of UAV-based soil erosion research to explore trends, technologies, and challenges. A systematic review of Web of Science and Scopus articles identified 473 relevant studies after filtering for terms that refer to types of soil erosion. Analysis using R’s bibliometrix package shows research is concentrated in Asia, Europe, and the Americas, with 304 publications following a surge. Multi-rotor UAVs with RGB sensors are the most common. Gully erosion is the most studied form of the issue, followed by landslides, rills, and interrill and piping erosion. Significant gaps remain in rill and interrill erosion research. The integration of UAVs with satellite data, laser surveys, and soil properties is limited but crucial. While challenges such as data accuracy and integration persist, UAVs offer cost-effective, near-real-time monitoring capabilities, enabling rapid responses to erosion changes. Future work should focus on multi-source data fusion to enhance conservation strategies.

Analyses for failure patterns of blanket defects on initiation of backward erosion piping

ABSTRACTSoil erosion, driven by factors such as water, wind, tillage and so forth, has significant impacts on both humanity and the environment. Soil erosion, including surface and subsurface (piping) erosion, significantly affects the environment and infrastructure. This research examines the impact of soil properties, that is, electrical conductivity (EC) and pH, on sediment yield in both surface and piping erosion. Rigorous laboratory experiments were conducted on slopes of 5%, 10% and 15%, using a soil profile that consisted of a 5 cm water‐restrictive layer of clay loam and a 15 cm topsoil layer of loam. Three experimental configurations were devised: exclusive pipe flow at 27 L h−1 (M1), rainfall intensity at 30 mm h−1 (M2), and a composite scenario integrating both rainfall and pipe flow (M3), with each configuration executed three times. The pipe flow was simulated using a plastic tube with a 1 cm diameter, placed on top of the water‐restrictive layer, which helped create conditions for subsurface flow. Results showed that sediment yield predictions varied with slope. For surface erosion, the most favourable performance was observed at 5% slope with pipe flow (R2 = 0.76, NSE = 0.76), while combined scenarios performed adequately (R2 = 0.71). At 10% slope, performance was good (R2 = 0.66, NSE = 0.65), and at 15%, results ranged from acceptable to very good. In piping erosion, the combined scenario consistently performed best (R2 = 0.78–0.91, NSE = 0.67–0.82), particularly at 5% and 15% slopes. These findings offer valuable insights into erosion dynamics and can help improve soil management strategies.

Abstract Internal erosion, characterized by the migration of soil particles within hydraulic earth structures due to seepage, is a significant global concern for risk management and maintenance. Among various mechanisms contributing to internal erosion, suffusion emerges as a prominent process. It involves the simultaneous detachment, transport, and potential self-filtration of fine particles through the pore network, leading potentially to a change in permeability and shear strength. Thus, investigating the link between permeability and microstructure is a key to achieve a better understanding of suffusion and to predict its consequences on the soil’s permeability. The proposed methodology involves generating discrete element method-based samples, characterizing their constriction size distribution, and computing permeability using fast Fourier transform. While the Kozeny-Carman model was initially developed for stable microstructures, it may not apply to suffusion due to microstructural evolution. Thus, a modified approach is introduced, incorporating a characteristic constriction diameter computed from the constriction size distribution. This modified model is being compared against the original Kozeny-Carman one on fourteen gap-graded specimens. Encouraging results are herein being obtained so that the modified approach will be later used on flow modified specimens.

Abstract Suction buckets are a promising concept for the foundations of offshore wind turbines. During the installation process of a suction bucket, localized fluidization of the granular soil, so-called piping erosion, may lead to installation failure. A 3D fluid-solid coupled micromechanical simulation is presented to study the occurrence of piping. An Euler-Lagrangian coupling employs momentum exchange between the fluid phase and the geometrically resolved particles. We investigate the behavior of the soil for three cases with varying prescribed suction velocities. We observe piping in the case with the highest suction velocity by analyzing the deformation of the granular fabric and monitoring the differential pressure. The grains under the bucket wall-tip show the highest hydraulic gradients and forces at the onset of piping. This approach permits a detailed analysis of piping phenomena and brings novel insights on the triggering conditions for piping failure of suction-aided foundations.

Abstract Internal erosion manifests as particle loss at the micro-pore scale in a soil matrix, else as particle loss at the macro-pore scale in cracks, fractures, pipes, and fissures. Risk management of internal erosion in dam safety engineering is, at the time of writing, entirely based on empirical screening methods. Empirical methods have no explanatory power, and this BC Hydro-NSERC funded research identifies the governing mechanics at the micro-pore scale in widely-graded cohesionless soil. Analysis of flexible-wall permeameter data on a sand-gravel test specimen, reconstituted from borrow pit material for the WAC Bennett Dam in Canada, establishes a novel relation in stress-gradient space for the initiation or triggering of internal instability in a susceptible gradation. The experimental relation appears consistent with the theoretical concept of a stress-reduction factor acting on the finer fraction content of a potentially unstable widely-graded soil.

Abstract The sand erosion detection sensor in the outlet pipe of the subsea tree is an effective tool to assess the extent to which subsea trees are affected by sand erosion during offshore oil and gas extraction operations. The subsea tree has intricate structures and numerous pipeline components, necessitating the study of the optimal installation position of the sand erosion detection sensor to ensure the detection sensitivity of the sensor. This paper carries out a simulation study to determine the optimal installation position of the sand erosion detection sensor in the outlet pipe of the subsea tree. By integrating correlation analysis, experimental data comparison and other methods, this paper analyzes and verifies that the liquid-flow sand erosion detection sensor should be installed at the 70° position on the first elbow, while the gas-flow sand erosion detection sensor should be installed at the 30° position on the elbow. This can realize the effective detection of sand erosion in the outlet pipe of subsea trees under different working conditions.

CFD-DEM Modeling of Loess Microstructure Alteration during Internal Hydraulic Erosion and Its Effect on Micro- to Macromechanical Behaviors

Seismic behavior of a shallow underground station with internal soil erosion

Copper Mountain Mine tailings dam slope stability research based on recommendations of the 2021 Tetra Tech Dam Safety Review, including computation of tailings dam factors of safety, satellite imagery, steady state and transient seepage analyses, and assessment of internal erosion risk. 3D dam factors of safety satisfy BC’s normal operating legal requirement of 1.5 but are in possible violation of the post-seismic legal requirement of 1.2.

The catastrophic floods in Poland in previous years and the current one in 2024 have highlighted the importance of slope stability in the design, maintenance, and operation of levees, which are crucial for flood protection. While the causes of this year's flood have not been determined yet, as experts are still working on assessing the reasons for the failure of various structures, it is evident that many have failed due to multiple factors, such as overtopping, internal erosion, and slope instability. The article highlights the importance of the observational method, which, during the operation of hydraulic structures often in use for decades, enables data collection on potential seepage through the levee and on adverse filtration phenomena. Such information allows revising previous safety calculations for the structure, adjustments of geotechnical parameters adopted during the design phase, and consideration of factors like the presence of water on the downstream side. Evaluating slope stability under these conditions reflects the actual working environment of the structure and facilitates decision-making regarding potential modernization initiatives. The article analyses the stability of the levee slope before and after its modernization. A transient seepage analysis through the levee was carried out in the selected cross-section for various water levels, and the stability of the embankment in such conditions was also assessed. Next, the modernization of the embankment was briefly described, with particular emphasis on the sealing system. Stability was evaluated under the new filtration conditions through the levee. Based on this, it was concluded that the sealing system plays a crucial role in improving the safety and stability of the slope. The analysis revealed that remedial actions alone—such as soil compaction and raising the levee crest—without the installation of sealing systems would have virtually no significant impact on the structure safety. After implementing the remedial measures, the levee safety factor can be considered safe, and the numerical analysis of water filtration through the levee indicates that future water seepage on the downstream side during river flooding should not occur.