Search Results (1,218)

This study investigates the undrained bearing capacity of strip foundations subjected to inclined loading on two-layer cohesive slopes using finite element limit analysis (FELA). Both lower bound (LB) and upper bound (UB) theorems with adaptive mesh refinement are employed to conduct comprehensive parametric analyses examining the influence of key geotechnical and geometric factors on the bearing capacity factor N_ci and associated failure mechanisms. The parameters investigated include the interlayer shear strength ratio c_u1/c_u2, load inclination angle α, upper layer thickness ratio D/B, setback distance b/B, normalized undrained shear strength of the upper layer c_u1/γB, and slope angle β. The results demonstrate that load inclination and interlayer strength contrast have a pronounced effect on the bearing capacity, while the failure mode transitions between foundation failure and overall slope failure depending on the geometric configuration. The numerical results are validated against existing published data, showing excellent agreement with a maximum relative error of 1.19%. Comprehensive design charts are provided to facilitate the bearing capacity estimation and failure pattern identification under various geometric and loading configurations, offering practical guidance for geotechnical engineers dealing with foundations on stratified slopes. Full article

Rapid landslide susceptibility screening is important for linear engineering projects because long corridors, numerous slope units, limited data, and tight schedules often restrict the use of data-intensive models. This study develops an engineering-oriented reduced-factor screening framework based on the Information Value (IV) model and applies the framework to the Beijing-Zhangjiakou Railway corridor. A conventional 10-factor IV model was first established as the reference model. Reduced-factor models were then screened under the same study area, the same landslide inventory, the same modelling workflow, and the same factor classification scheme. The 10-factor model reached an accuracy of 94.87%. Two reduced five-factor models reached the same accuracy: Slope + Aspect + Elevation + Lithology and Engineering Rock + NDVI, and Slope + Aspect + Elevation + Lithology and Engineering Rock + Distance to Rivers. The comparison shows that the full-factor model can be simplified without loss of validation accuracy when a stable terrain–geological framework is retained and a suitable external factor is added. Because the available inventory contains only 45 landslides and does not distinguish failure mechanisms consistently, the proposed model should be regarded as a preliminary probabilistic screening tool rather than a mechanism-specific prediction model. The proposed framework provides a practical approach for corridor-scale hazard screening under incomplete data conditions. Full article

Rock–fill composite slopes formed during the transition from underground to open-pit mining in metal mines are highly susceptible to interface hydraulic weakening and sudden sliding under intense rainfall, mainly due to the permeability contrast between the two media. Taking the Shizhuyuan Mine as a case study, a coupled hydro-mechanical numerical model was developed in ABAQUS 2025 to investigate slope stability under different rainfall patterns and interface strength degradation scenarios. The spatiotemporal evolution of seepage and deformation fields was examined in detail, with particular attention given to the variation of the safety factor, the distribution of pore water pressure along the interface, and the characteristics of interface slip. The results show that: (1) the deterioration of the hydraulic condition within the slope is governed by the water-blocking effect of the interface and the infiltration threshold of the surface layer. Under the same total rainfall, prolonged low-intensity rainfall is more likely than short-duration intense rainfall to produce sustained deep infiltration, and the factor of safety decreases from the initial 1.369 to 1.173 (0.005 m/h, 288 h) and 1.255 (0.02 m/h, 72 h), respectively, indicating that the former exerts a more pronounced weakening effect on slope stability. (2) Slope instability exhibits a clear interface-controlled pattern. Regardless of the degree of parameter degradation, the base of the plastic zone consistently develops along the rock–fill interface, accompanied by extensive plastic deformation within the overlying fill material. (3) Failure initiates at the slope toe where the mechanical equilibrium along the rock–fill interface is first disturbed. Under the combined influence of topographic conditions and the water-blocking effect of the interface, rainfall infiltration tends to converge toward the slope toe and form a local high-pore-pressure zone, resulting in a marked reduction in the effective normal stress at the interface. Once the local shear stress exceeds the shear strength, yielding is triggered first at the slope–toe interface, which then induces plastic deformation in the overlying fill material and ultimately leads to overall slope instability. Full article

At around 8:40 a.m. on 17 July 2024, the Wanshuitian landslide in the Three Gorges Reservoir Area (TGRA) experienced a deformation failure characterized by thrust load-caused deformations and high-speed sliding. Using geological surveys and unmanned aerial vehicle (UAV) photography, this study divided the Wanshuitian landslide area into five zones: sliding initiation (A1), secondary disintegration (A2), main accumulation (B1), right falling (B2), and left falling (B3) zones. Through monitoring data analysis and GeoStudio-based numerical simulations, this study revealed the mechanisms behind the landslide failure mode characterized by slope sliding approximately along the strike of the rock formation under the coupling effect of hydrological and geological conditions. The results indicate that factors inducing the landslide failure include the geomorphic feature of alternating grooves and ridges, the lithologic assemblage characterized by interbeds of soft and hard rocks, the slope structure with well-developed joints, and the sustained heavy rains in the preceding period. In the Wanshuitian landslide area, mudstone valleys are prone to accumulate rainwater, which can infiltrate directly into the weak interlayers of rock masses and soften the rock masses. Multi-peak rain events with a short time interval serve as a critical factor in groundwater recharge. Within 17 days preceding its failure, the Wanshuitian landslide experienced a superimposed process of heavy and secondary rain events with a short interval (four days). Rainwater from the first heavy rain event failed to completely discharge during the short interval, while the secondary rain event also caused rainwater accumulation. These led to a continuous rise in the groundwater table, a constant decrease in the shear strength of the slope, and ultimately the landslide instability. Since the landslide sliding in the dip direction of the rock formation was impeded, the main sliding direction of the landslide formed an angle of 88° with this direction. This led to a unique failure mode characterized by slope sliding approximately along the strike of the rock formation. Based on these findings, this study proposed characteristics for the early identification of the failure of similar landslides, aiming to provide a robust scientific basis for the monitoring, early warning, and prevention and control of the failure of similar landslides. Full article

Objective: To investigate the association between pelvic incidence (PI) and fixation failure following single-level transforaminal lumbar interbody fusion (TLIF) for low-grade spondylolisthesis and to identify risk factors for pedicle screw loosening. Methods: This retrospective study included 80 patients who underwent single-level TLIF and were divided into a high PI group (n = 40) and a normal/low PI group (n = 40). Radiographic parameters including PI, lumbar lordosis (LL), pelvic tilt (PT), sacra l slope (SS), listhesis magnitude, and PI–LL mismatch were evaluated pre- and postoperatively. Screw loosening and fusion status were assessed at 6, 12, and 24 months. Multivariate logistic regression analysis was performed to identify independent risk factors for screw loosening. Results: The high PI group demonstrated significantly higher screw loosening rates than the normal/low PI group at all follow-up time points, with a rate of 57.5% versus 28.2% at 24 months (p = 0.012). Fusion rates were comparable between groups. Multivariate analysis identified high PI and residual listhesis were independent risk factors for screw loosening (Odds ratio 1.05 and 1.35). PI–LL mismatch > 10° showed higher odds but were not statistically significant. Conclusions: High PI is associated with an increased risk of pedicle screw loosening after single-level TLIF. Careful preoperative assessment and postoperative monitoring may help reduce fixation-related complications. Full article

While check dams are crucial for debris flow mitigation, they face increasing failure risks under extreme weather and seismic activities. Their collapse can severely amplify debris flow magnitude, yet quantitative understanding of this amplification mechanism remains limited. Based on field investigations in southern Gansu, China, and a total of 12 flume experiments (comprising 11 distinct scenarios and 1 representative repeatability test), this study quantitatively assesses the amplification effect of dam breaches under varying channel slopes, check dam types, and bed conditions. Results indicate that dam-breach debris flow evolution comprises three stages: material initiation and deposition, breaching and material release, and recession. Crucially, dam breaching shifts the initiation mode from progressive retrogressive erosion to a near-instantaneous release of mass and potential energy. Compared to no-dam scenarios, breaches amplified peak discharge, erosion rate, and downstream inundated area by factors of 1.65–3.04, 1.44–1.55, and 2.14–2.77, respectively. This amplification is driven by the rapid initial release of material and energy, compounded by erosional entrainment during the transport phase. Furthermore, check dam type and channel slope act as key controlling factors. By revealing how check dams transition from protective structures to hazard sources, this study provides quantitative experimental evidence for optimizing dam design and advancing resilient disaster risk reduction strategies in mountainous regions. Full article

This study re-examines two geologically and geotechnically similar geosynthetic-reinforced soil walls with modular block facings (GRS-MBs) that exhibited markedly different seismic performances during the 1999 Chi-Chi earthquake (M_L = 7.3). Integrating a multi-wedge failure mechanism that captures soil–facing–reinforcement interactions with a nonlinear hyperbolic soil model representing shear stress–displacement behavior along the slip surface, the Force–equilibrium-based Finite Displacement Method (FFDM) provides consistent and robust displacement evaluations over a wide range of input seismic inertial forces. A systematic sensitivity investigation confirms that the FFDM framework responds to parameter variations in a physically meaningful manner, and that displacement predictions remain stable with respect to reasonable uncertainties in soil, reinforcement, and facing properties. The analysis clarifies why two similar GRS-MBs responded so differently during strong shaking and demonstrates the broader applicability of FFDM for displacement-based seismic assessment, including under shaking levels (e.g., k_h ≈ 0.3) that would drive conventional limit–equilibrium calculations to F_s < 1.0, a physically impossible state requiring shear resistance greater than the soil’s ultimate strength. A comparative evaluation of seismic displacement predictions using the Newmark method and FFDM shows that FFDM successfully generates displacement-based seismic resisting curves and reproduces field-observed displacements. In contrast, the Newmark method yields order-of-magnitude variability in predicted movements and may be unsuitable for displacement-sensitive engineered slopes where deformations on the order of several 10⁻³–10⁻² m are practically significant. For interaction-rich GRS-MBs with high values of k_hc, beyond the predictive capability of Newmark’s equation, FFDM offers a practical and physically grounded tool for seismic displacement assessment of reinforced soil structures. Full article

Utilizing lunar regolith as a raw material for structural components offers significant potential for future lunar exploration. Direct manufacturing from unprocessed regolith reduces the need for specialized refining equipment compared to element extraction methods. At present, the mechanical properties of long-term alkali-activated CQU-1 lunar regolith simulant geopolymer (LRSG) columns have not been studied. To address this, forty-eight CQU-1 LRSG cylindrical specimens were prepared and tested under axial compression in this study. The effects of the curing temperature (60 °C and 80 °C), curing time (3 d, 7 d, 14 d and 28 d), and water–binder ratio (0.325 and 0.455) on the failure modes and stress–strain behavior were investigated. The alkali-activated CQU-1 LRSG achieved a maximum compressive strength of 33.89 MPa under optimal conditions. Elevated curing temperatures and extended curing times enhanced peak stress and elastic modulus while reducing peak and ultimate strains, indicating greater stiffness and brittleness. Conversely, increased water–binder ratios flattened stress–strain curves, diminishing slope and peak stress while elevating peak and ultimate strains. Based on these test results, the stress–strain model, elastic modulus model and peak strain model of alkali-activated CQU-1 LRSG were proposed. The proposed models can accurately predict the stress–strain relationship, compressive strength and ultimate strain of alkali-activated CQU-1 LRSG. The influence of curing temperature, curing time, and water–binder ratio on the performance of alkali-activated CQU-1 LRSG is also discussed in detail. This work confirms the viability of the alkali-activated CQU-1 LRSG and lunar regolith-based geopolymers for future extraterrestrial construction. Full article

In heart failure (HF), elevated blood lactate levels, particularly during exercise or in advanced disease stages, reflect impaired tissue perfusion and altered metabolic regulation. Beyond its traditional role as a marker of anaerobic metabolism, lactate has emerged as a dynamic indicator of metabolic reserve and ventilatory control. This narrative review summarizes current evidence on lactate dynamics at rest and during exercise, highlighting their pathophysiological and clinical relevance. In HF patients, exercise-induced lactate accumulation occurs earlier and at lower workloads, reflecting impaired oxidative capacity and reduced peripheral oxygen utilization. This phenomenon is closely associated with ventilatory inefficiency, as demonstrated by the relationship between lactate levels and the VE/VCO₂ slope during cardiopulmonary exercise testing (CPET). Emerging data suggest that lactate is not only a marker of disease severity but also a potential mediator of chemoreflex activation and abnormal ventilatory responses. Furthermore, both pharmacologic and non-pharmacologic interventions may influence lactate production and utilization, supporting its role as a potential tool for therapeutic monitoring. Overall, the integration of lactate assessment, particularly during exercise, into clinical evaluation may provide additional insight into disease mechanisms, improve risk stratification, and contribute to personalized therapeutic optimization in patients with HF. Full article

Open-pit mining operations rely heavily on visual inspection to identify indicators of slope instability such as surface cracks. Early identification of these geotechnical hazards enables timely safety interventions to protect both workers and assets in the event of slope failures or landslides. While computer vision (CV) approaches offer a promising avenue for autonomous crack detection, their effectiveness remains constrained by the scarcity of labelled geotechnical datasets. Deep learning (DL)-based models, in particular, require large amounts of representative training data to generalize to unseen conditions; however, collecting such data from operational mine sites is limited by safety, cost, and data confidentiality constraints. To address this challenge, this study proposes a novel hybrid game engine–generative artificial intelligence (AI) framework for large-scale dataset generation without requiring real-world training data. Leveraging a parameterized virtual environment developed in Unreal Engine 5 (UE5), the framework generates realistic images of open-pit surface cracks and enhances their fidelity and diversity using StyleGAN2-ADA. The synthesized datasets were used to train the YOLOv11 real-time object detection model and evaluated on a held-out real-world dataset of open-pit slope imagery to assess the effectiveness of the proposed framework in improving model generalizability under extreme data scarcity. Experimental results demonstrated that models trained using the proposed framework consistently outperformed the UE5 baseline, with average precision (AP) at intersection over union (IoU) thresholds of 0.5 and [0.5:0.95] increasing from 0.792 to 0.922 (+16.4%) and 0.536 to 0.722 (+34.7%), respectively, across the best-performing configurations. These findings demonstrate the effectiveness of hybrid generative AI frameworks in mitigating data scarcity in CV applications and supporting the development of scalable automated slope monitoring systems for improved worker safety and operational efficiency in open-pit mining. Full article

Submarine canyon-channel systems play a critical role as potential conduits for warm-water upwelling around Antarctica, potentially influencing ice-sheet stability. Integrating multibeam bathymetry, seismic profiles, and morphometric analysis, this study identifies 29 canyon-channel systems along the Adélie Land margin and reveals clear morphological contrasts between the Adélie Depression and the Adélie Bank. Systems in the Depression are elongated, slightly sinuous, and dendritic, with downstream increases in width-to-depth ratio, whereas those on the Bank are shorter, isolated, and single-branched, with irregular along-thalweg variations. Mann–Whitney U tests show significant differences in sinuosity and thalweg gradient (p < 0.01). These contrasts reflect the combined effects of shelf-slope topography, sediment supply, and ice-sheet dynamics. In the Depression, steep slopes, focused glacial sediment input from the Wilkes Subglacial Basin, and associated progradational wedges and mass transport deposits promote mass failures and turbidity-current incision. Strong correlations among canyon-channel length, width, and depth indicate coherent scaling under concentrated sediment supply. In contrast, gentler slopes and lower sediment input on the Bank produce simpler systems. These results highlight how glaciated-margin canyon morphology records coupled sedimentary and ice-sheet–ocean processes. Full article

The Taoping paleo-landslide poses a significant risk to local residents and critical infrastructure. However, traditional field surveys and deformation monitoring methods are often inadequate for capturing subtle, localized deformation characteristics—particularly at the head scarp and lateral margins—thereby limiting comprehensive assessments of slope instability. Surface strain data offer direct insights into internal stress redistribution during slope evolution and are essential for interpreting landslide mechanisms and forecasting failure. Given the current limitations in dense and wide-area strain monitoring technologies, this study proposes a novel method for modeling landslide strain fields based on Interferometric Synthetic Aperture Radar (InSAR) phase gradients. Using the phase gradient stacking approach, InSAR-derived phase gradients are transformed into strain-related parameters, enabling estimation of shear strain rates, principal strain rates, and their directional distributions. The application to the Taoping paleo-landslide reveals clear spatial patterns of compressive and tensile strain across the landslide body. Field investigations corroborate the InSAR-derived strain features through corresponding geomorphological evidence observed in both compressional and extensional zones. The proposed method enhances the understanding of landslide deformation behavior, supports evaluation of shear surface continuity and evolution, and offers a robust framework for early warning and risk mitigation in complex landslide-prone areas. Full article

Cement concrete is a critical pavement construction material. However, under prolonged exposure to heavy traffic loads and the combined effects of multiple factors, it frequently exhibits premature slab failure and concurrent multiple defects, severely limiting its service performance and lifespan. The dynamic behavior of cement concrete pavement under heavy-load conditions and the influence of subgrade geometry and pavement width on dynamic bearing performance remain insufficiently understood. To address this issue, this study employs finite element software Abaqus 2020 to construct a three-dimensional finite element model of heavy-duty cement concrete pavement under six typical conditions, including uncut and unfilled subgrade, low embankment, high embankment, cut slope, and different pavement widths. Utilizing an implicit dynamic algorithm, the model simulates and analyzes the acceleration response, dynamic stress distribution, and evolution of strain energy density within the pavement structure under vehicle dynamic loading. The results indicate that the peak acceleration is highest for the uncut subgrade (159.214 m/s²) and lowest under the cut condition (146.566 m/s²), demonstrating that the cutting structure can effectively suppress pavement vibration intensity. Among subgrade types, high embankments exhibit the greatest capacity for reducing strain energy concentration; at the slab corners, the baseline strain energy density of 8.882 J/m³ is reduced by 4.2%, 7.8%, and 5.0% under low embankment, high embankment, and cut conditions, respectively. Regarding pavement width, wider configurations reduce slab vibration intensities, stored strain energy, peak stresses, and stress concentrations, benefiting long-term service life, but concurrently elevate slab corner strain energy accumulation, increasing the risk of corner fracture and compromising load-bearing capacity. These findings provide scientific and technical support for the structural design and performance optimization of heavy-duty cement concrete pavements. Full article

The Tuzla Submarine Landslide represents one of the most significant mass-wasting features associated with the active North Anatolian Fault Zone (NAFZ). The failure surface geometry and sediment stratigraphy indicate the presence of a mechanically weak, saturated layer that may become unstable under strong seismic loading. This study presents a comprehensive geotechnical evaluation of the Tuzla Submarine Landslide. Based on regional sediment properties, the landslide was characterized and modeled with an estimated volume of 0.015 km³ and an average slope angle of 14°. The submarine landslide potential was investigated through re-analysis of seismic, geotechnical, and bathymetric datasets. Finite Element Method (FEM) simulations were conducted to model the seismic slope failure. Based on these analyses, the seismic slope displacements, stress distributions, and equivalent plastic strains were identified. The estimated landslide displacements under varying seismic acceleration scenarios corresponding to three major earthquakes ranged between 2.38 m and 4.12 m, depending on the triggering ground motion and slope stability conditions. These findings highlight that reactivation of the Tuzla submarine landslide, potentially triggered by a future large earthquake along the NAFZ, could pose a moderate landslide hazard to the coastal settlements bordering the Marmara Sea. Full article

As one of the most catastrophic geological hazards globally, landslides exhibit heightened risks due to their increasing frequency, destructive potential, and extensive spatial distribution. The primary objective of this study is to develop an integrated analytical framework to quantitatively evaluate the stability of variably shaped slopes under rainfall infiltration. The core hypothesis is that slope curvature significantly alters infiltration behavior and stress distribution, leading to morphology-dependent failure mechanisms. Employing Green-Ampt infiltration theory coupled with limit equilibrium analysis, we establish stability prediction models for three fundamental slope geometries (linear, concave, convex) under contrasting rainfall regimes (high-intensity vs. low-intensity precipitation). The derived analytical solutions reveal two critical phenomena: (1) progressive downward migration of the saturation front maintaining parallelism with slope surfaces during infiltration and (2) time-dependent stability deterioration following hyperbolic decay patterns. The proposed models are rigorously validated through numerical simulations employing finite element methods, which demonstrate remarkable congruence with theoretical predictions, showing safety factor discrepancies below 5% (ΔFs < 0.05). Particularly, concave slopes exhibit 18–22% faster destabilization rates compared to convex counterparts under equivalent rainfall conditions. The validated models elucidate the spatiotemporal evolution of matric suction and pore pressure distributions, providing quantitative insights into morphology-dependent failure thresholds. These findings advance predictive capabilities for rainfall-induced landslides through physics-based stability criteria, offering critical guidance for terrain-specific early warning systems and mitigation strategies in geohazard-prone regions. Full article