Search Results (1,864)

The objective of this paper was to investigate and design a novel vertical- and horizontal-arm independent suspension system aimed at enhancing the autonomous obstacle-crossing capabilities of unmanned ground platforms in complex, unstructured environments such as mountainous regions, hills, and mining areas. By thoroughly considering factors such as the suspension structure design, changes in the centroid position, distribution of driving forces, and dynamic stability analysis, we proposed an innovative suspension structure. An unmanned ground platform model equipped with this suspension system was developed using ADAMS and MATLAB/Simulink. Subsequently, a joint simulation was conducted to validate the performance of the suspension system. The results indicated that the unmanned ground platform could successfully traverse vertical steps up to 370 mm high and trenches measuring up to 600 mm wide. Furthermore, when confronted with intricate obstacles including vertical barriers, trenches, and side slopes, the platform demonstrated exceptional traversing capabilities. In conclusion, the proposed suspension system significantly enhances both the obstacle-surmounting ability and the terrain adaptability of unmanned ground platforms while providing crucial technical support for their deployment in complex unstructured environments. Full article

Slope displacement monitoring is essential for assessing slope stability and preventing catastrophic failures, particularly in geotechnically sensitive areas. However, continuous data collection is often disrupted by environmental factors, sensor malfunctions, and communication issues, leading to missing data that can compromise analysis accuracy and reliability. This study addresses these challenges by evaluating advanced machine learning models—SAITS, ImputeFormer, and BRITS (Bidirectional Recurrent Imputation for Time Series)—for missing data imputation in slope displacement datasets. Sensors installed at two field locations, Yangyang and Omi, provided high-resolution displacement data, with approximately 34,000 data points per sensor. We simulated missing data scenarios at rates of 1%, 3%, 5%, and 10%, reflecting both random and block missing patterns to mimic realistic conditions. The imputation performance of each model was evaluated using Mean Absolute Error, Mean Squared Error, and Root Mean Square Error to assess accuracy and robustness across varying levels of data loss. Results demonstrate that each model has distinct advantages under specific missingness patterns, with the ImputeFormer model showing strong performance in capturing long-term dependencies. These findings underscore the potential of machine learning-based imputation methods to maintain data integrity in slope displacement monitoring, supporting reliable slope stability assessments even in the presence of significant data gaps. This research offers insights into the optimal selection and application of imputation models for enhancing the quality and continuity of geotechnical monitoring data. Full article

Mitigating global warming necessitates transitioning from fossil fuels to alternative energy carriers like hydrogen. Efficient hydrogen production via electrocatalysis requires high-performance, stable anode materials for the oxygen evolution reaction (OER) to support the hydrogen evolution reaction (HER) at the cathode. Developing noble metal-free electrocatalysts is therefore crucial, particularly for acidic electrolytes, to avoid reliance on scarce and expensive metals such as Ir and Ru. This study investigates a low-cost, solvent-free solid-state synthesis of CoSb₂O₆, focusing on the influence of calcination time and temperature. Six samples were prepared and characterized using powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (BET) analysis, field-emission scanning electron microscopy (FESEM), and electrochemical techniques. A non-pure CoSb₂O₆ phase was observed across all samples. Electrochemical testing revealed good short-term stability; however, all samples exhibited Tafel slopes exceeding 200 mV dec⁻¹ and overpotentials greater than 1 V. The sample calcined at 600 °C for 6 h showed the best performance, with the lowest Tafel slope and overpotential, attributed to its high CoSb₂O₆ content and maximized {110} facet exposure. This work highlights the role of calcination protocols in developing Co-based OER catalysts and offers insights for enhancing their electrocatalytic properties. Full article

A smart regenerative braking system for EVs can reduce unnecessary brake operations by assisting in the braking of a vehicle according to the driving situation, road slope, and driver’s preference. Since the strength of regenerative braking is generally determined based on calibration data determined during the vehicle development process, some drivers could encounter inconveniences when the regenerative braking is activated differently from their driving habits. In order to solve this problem, various deep learning-based algorithms have been developed to provide driving stability by learning the driving data. Among those artificial intelligence algorithms, anomaly detection algorithms can successfully separate the deceleration data in abnormal driving situations, and the resulting refined deceleration data can be used to train the regression model to achieve better driving stability. This study evaluates the performance of a personalized driving assistance system by applying driver characteristic data, obtained through an anomaly detection algorithm, to vehicle control. Full article

Biocementation is an innovative and sustainable technique with wide-ranging applications in slope stabilization, watershed management, and erosion control. Despite its potential, comprehensive evaluations of its use in hydrology and geotechnical engineering are limited. This study addresses this gap through a bibliometric analysis of 685 articles (2013–2023) from the Scopus database, employing VOSviewer and RStudio to explore global research trends, key contributors, and emerging themes. The analysis reveals that China, the United States, and Japan are leading contributors to this field, with significant advancements in microbial-induced (MICP) and enzyme-induced calcium carbonate precipitation (EICP) techniques. These methods have demonstrated effectiveness in improving soil strength, reducing erosion, and enhancing hydrological properties such as infiltration, runoff control, and water retention. Co-occurrence analysis identifies interdisciplinary connections between geotechnics and hydrology, highlighting research clusters focused on biomineralization, erosion resistance, and durability. The findings underscore biocementation’s pivotal role in addressing sustainability challenges by providing environmentally friendly alternatives to traditional soil stabilization techniques. This study not only maps the current research landscape but also offers valuable insights into the practical implications of biocementation for slope stability and hydrological management, laying the foundation for future advancements in sustainable engineering practices. Full article

The Shenhu area, located on the northern continental slope of the South China Sea, is a confirmed gas hydrate-enriching region, but the sedimentary unit, causative mechanisms, and evolution processes of the strata that contain hydrate remain unclear. Furthermore, the recognition of bottom simulating reflectors (BSRs) rests on qualitative description; there is no quantitative method for the characterization or three-dimensional depiction of BSRs. This review examines the sedimentary features and key factors controlling gas hydrate distribution in the region, based on high-resolution sequence stratigraphy combined with drilling and logging data from hydrate drilling projects in the Shenhu area. The main findings of this study include (1) BSRs are mainly distributed in the ridges of the continental slope and in the slip blocks of the side slope, with hydrates developing along a thin layer (10–40 m) below the hydrate stability zone, as confirmed by drilling results; (2) The distribution of BSRs is strongly influenced by the presence of gas chimneys, the migration of deepwater channels, and the erosion and sedimentation processes of canyons, all of which are directly or indirectly related to the accumulation, distribution, and formation of hydrate reservoirs; (3) The sand factor is generally less than 10%, and BSRs accumulate in areas where the sand factor is higher (4–10%). Hydrate saturation shows a positive correlation with porosity. This research also identifies the early Pleistocene erosion/resedimentation event as a key factor that controls the non-homogeneous distribution of hydrates in the region. This research highlights the role of deepwater canyon erosion and slumping processes in controlling gas hydrate formation, offering new insights into the impact of dynamic geological processes on hydrate accumulation. This study provides valuable knowledge for future hydrate exploration and global resource assessments. Full article

Taiwan is located at a junction of tectonic plates, which results in frequent earthquakes. Its terrain is mostly hilly, and its rainfall ranks among the highest in the world. Each of these elements affects the stability of slopes in various regions of Taiwan. Several slopes along Taiwan’s Freeway 1 and 5 have experienced landslides and rockfalls. It is imperative that the slope stability of these national freeways be analyzed to avoid future slope collapses brought on by precipitation or other outside factors. Thus, three sites on Taiwan’s Freeway 1 and 5 were chosen for numerical slope stability analysis in this study. PLAXIS 2D CE (Version: 24.02.00.1144) finite element software was used in this study to simulate and analyze the safety of freeway slope protection projects. Displacements induced by normal and high groundwater levels were discussed. Moreover, a pseudo-static study of slope displacements under seismic conditions was performed. According to the results of the numerical study, the force operating on the slope was centered on the sliding surface when the groundwater level was normal, and it extended to the top when the groundwater level was high. By comparison, under seismic conditions, the force acting on the slope extended to the whole slope. Furthermore, the slope safety factor of Site 1 was greater than the design specification value in three different scenarios. This confirms that the slope protection project at Site 1 is effective. Full article

Climate change has led to an increasing frequency of droughts, potentially undermining soil stability. In such a changing environment, the shallow reinforcement effect of plant roots often fails to meet expectations. This study aims to explore whether this is associated with the alteration of plant traits as a response to environmental change. Focusing on Amorpha fruticosa, a species known for its robust root system that plays a crucial role in soil consolidation and slope stabilization, thereby reducing soil and water erosion, we simulated a drought-rewetting event to assess the legacy effects of drought on the soil shear strength and the mechanical and hydrological traits associated with the reinforcement provided by A. fruticosa. The results show that the legacy effect of drought significantly diminishes the soil shear strength. Pretreated with drought, plant roots undergo morphological alterations such as deeper growth, yet the underground root biomass and diameter decline, thereby influencing mechanical reinforcement. Chemical composition analysis indicates that the plant’s adaptation to drought modifies the intrinsic properties of the roots, with varying impacts on different root types and overall reinforcement. Concurrently, the stomatal conductance and transpiration rate of leaves decrease, weakening the capacity to augment soil matric suction through transpiration and potentially reducing hydrological reinforcement. Although rewetting treatments aid in recovery, drought legacy effects persist and impact plant functional attributes. This study emphasizes that, beyond soil matric suction, plant adaptive mechanisms in response to environmental changes may also contribute significantly to reduced soil shear strength. Consequently, ecological restoration strategies should consider plant trait adaptations to drought, enhancing root systems for soil conservation and climate resilience. Full article

Due to Paleo-clay’s unique properties and widespread distribution throughout China, it is essential in geotechnical engineering. Rainfall frequently causes the deformation of Paleo-clay slopes, making slope instability prediction crucial for disaster prevention. This study explored Paleo-clay’s strength degradation and slope stability under soaking and wet–dry cycles. Using Mohr–Coulomb failure envelopes from experiments, curve fitting was used to find the patterns of Paleo-clay strength degradation. Finite element simulations and the strength discounting method were used to analyze the stability and deformation of Paleo-clay slopes. The results indicate that wet–dry cycles impact them more than soaking. Paleo-clay’s cohesion decreases exponentially as the number of wet–dry cycles and soaking times rise, but the internal friction angle changes very little. After 10 wet–dry cycles and 24 days of soaking, iron-bearing clay’s cohesion decreased to 17% and 44% and reticular clay’s to 32% and 48%. Based on the study area characteristics, three slope types were constructed. Their stability exhibited exponential decay. Under soaking, stability remained above 1.4; under wet–dry cycles, type I and II stability fell below 1.0, leading to deformation and failure. All types showed traction landslides with sliding zones transitioning from deep to shallow. Practical engineering should focus on the shallow failures of Paleo-clay slopes. Full article

To address the issues of easy overturning and poor safety of crawler work machines operating on steep slopes in hilly and mountainous areas, this study develops a structural design scheme based on a “three-layer frame” structure. An omnidirectional leveling system with hydraulic interconnection is designed to maintain platform stability by ensuring a stationary central point during leveling. Furthermore, a sliding mode synchronization control method based on a disturbance observer is proposed to reduce the synchronization error of the hydraulic cylinders and enhance leveling precision. The system’s performance is validated through an AMESim-MATLAB/Simulink co-simulation platform, demonstrating significant improvements over traditional PID control. Specifically, both lateral and longitudinal leveling times are reduced, rise time decreases by 21.8% on average, and overall leveling time is reduced by 35.5%, with synchronization errors maintained within ±6 × 10⁻⁴ m. Finally, physical prototype testing further confirms the system’s effectiveness, achieving an average body inclination error of 2.55% and a hydraulic cylinder synchronization error of 8.2%. These findings validate the feasibility and superiority of the proposed omnidirectional leveling system for the crawler work machine in hilly and mountainous regions. Full article

Watersheds are critical ecosystems that provide essential services, but they face increasing threats from deforestation, land use changes, and climate variability. The Mata Allo Sub-Watershed, which is characterized by steep topography and high rainfall, is particularly vulnerable to erosion, landslides, and habitat loss, necessitating robust conservation strategies. This study used principal component analysis (PCA) to assess ecological sensitivity, focusing on slope, rainfall, vegetation density, and land cover. The PCA results identified land cover as the most influential positive factor in F1 (loading value: 0.588), increasing sensitivity due to human-induced land use changes, while rainfall contributed most negatively (−0.638) by potentially mitigating extreme ecological risks. These contrasting roles underscore the complexity of interactions shaping watershed sensitivity. Slope strongly influenced F2 (−0.795), explaining 26.48% of the variance and highlighting the critical role of steep slopes in exacerbating erosion risks. Vegetation density in F3 (−0.679) and rainfall in F4 (−0.724) played significant roles in stabilizing soil and mitigating ecological risks, emphasizing their importance in reducing watershed sensitivity. The “Extremely Sensitive” class covers 48.79% of the watershed, primarily in areas with steep slopes and sparse vegetation, while “High Sensitivity” areas occupy 34.93%. Projections for 2032 suggest a reduction in “Extremely Sensitive” zones to 41.00%, reflecting improvements from targeted management interventions. These findings provide a foundation for promoting sustainable watershed management, enhancing climate resilience, and supporting biodiversity conservation efforts in vulnerable regions. Full article

Rainfall-induced landslides are widely distributed in many countries. Rainfall impacts the hydraulic dynamics of groundwater and, therefore, slope stability. We derive an analytical solution of slope stability considering effective rainfall based on the Richards equation. We define effective rainfall as the total volume of rainfall stored within a given range of the unsaturated zone during rainfall events. The slope stability at the depth of interest is provided as a function of effective rainfall. The validity of analytical solutions of system states related to effective rainfall, for infinite slopes of a granite residual soil, is verified by comparing them with the corresponding numerical solutions. Additionally, three approaches to global sensitivity analysis are used to compute the sensitivity of the slope stability to a variety of factors of interest. These factors are the reciprocal of the air-entry value of the soil α, the thickness of the unsaturated zone L, the cohesion of soil c, the internal friction angle ϕ related to the effective normal stress, the slope angle β, the unit weights of soil particles γ_s, and the saturated hydraulic conductivity K_s. The results show the following: (1) The analytical solutions are accurate in terms of the relative differences between the analytical and the numerical solutions, which are within 5.00% when considering the latter as references. (2) The temporal evolutions of the shear strength of soil can be sequentially characterized as four periods: (i) strength improvement due to the increasing weight of soil caused by rainfall infiltration, (ii) strength reduction controlled by the increasing pore water pressure, (iii) strength reduction due to the effect of hydrostatic pressure in the transient saturation zone, and (iv) stable strength when all the soil is saturated. (3) The large α corresponds to high effective rainfall. (4) The factors ranked in descending order of sensitivity are as follows: α > L > c > β > γ_s > K_s > ϕ. Full article

Drilling and blasting is the conventional method used for rock fragmentation in open pit mining. Blast-induced damage can reduce the level of stability of benches and pit slopes. To develop an optimal blast design, an adequate knowledge of the rock properties and in situ fractures is needed. Fractures are generally the paths of least resistance for explosive energy and can affect the intensity of blast-induced damage. Discrete Fracture Networks (DFNs) are 3D representations of joint systems used for estimating the distribution of in situ fractures in a rock mass. The combined finite/discrete element method (FDEM) can be used to simulate the complex rock breakage process during a blast. The objective of this paper is to develop a methodology for assessing the influence of in situ joints on post-blast fracturing and the associated wall damage in 2D bench blast scenarios. First, a simple one-blasthole scenario is analyzed with the FDEM software Irazu 2D and calibrated based on a laboratory-scale blasting experiment available from previous literature. Secondly, more complex scenarios consisting of one-blasthole models at the bench scale were simulated. A bench blast without DFN (base case) and one with DFN were numerically simulated. The model with DFN demonstrated that the growth path and intensity of blast-induced fractures were governed by pre-existing fractures, which led to a smaller wall damage area. The damage intensity for the base case scenario is about 82% higher than for the blast model with DFN included, which highlights the significance of in situ fractures in the resulting blast damage intensity. The methodology for developing the DFN-included blasting simulation provides a more realistic modeling process for blast-induced wall damage assessment. This results in a better characterization of the blast damage zone and can lead to improved slope stability analyses. Full article

In order to study the stability of rock layers and the change in volumetric water content at different stages of mining under an environment of heavy rainfall, a self-developed large-scale open-pit-to-underground-mining similar physical model was used, and the intensity of continuous rainfall was set at 40 mm/h. The results of this study show that fissures accelerated the instability of rock strata, and when spreading to different rock strata, they were prone to form subsidence cracks and produce collapse zones. The volumetric water content is closely related to the stability of the rock formation. An ‘arch-shaped collapse zone’ was formed in an interval of (0.9~1.8 m), and a convex spreading zone of volumetric water content was formed in an interval of (1.2~1.6 m). The infiltration line shows different diffusion patterns in different mining stages. In the early stage of mining, the volumetric water content infiltration line is roughly parallel to the slope; in the middle stage of mining, the infiltration line diffuses parallel to the two ends of the interface with the slope and diffuses convexly in the middle; in the late stage of mining, the infiltration line shows a pattern of rapid diffusion in the lower area, rapid diffusion in the middle area, and slow diffusion in the middle area. Therefore, in the process of the mining stage, it is necessary to focus on mining area fissure changes and monitor the point water content for sudden changes and other indicators. This study has certain guiding significance for safe production. Full article

Mixed-metal nickel-iron, Ni_xFe materials draw attention as affordable earth-abundant electrocatalysts for the oxygen evolution reaction (OER). Here, nickel and mixed-metal nickel-iron metal–organic framework (MOF) composites with the carbon materials ketjenblack (KB) or carbon nanotubes (CNT) were synthesized in situ in a one-pot solvothermal reaction. As a direct comparison to these in situ synthesized composites, the neat MOFs were postsynthetically mixed by grinding with KB or CNT, to generate physical mixture composites. The in situ and postsynthetic MOF/carbon samples were comparatively tested as (pre-)catalysts for the OER, and most of them outperformed the RuO₂ benchmark. Depending on the carbon material and metal ratio, the in situ or postsynthetic composites performed better, showing that the method to generate the composite can influence the OER activity. The best material Ni₅Fe-CNT was synthesized in situ and achieved an overpotential (η) of 301 mV (RuO₂ η = 354 mV), a Tafel slope (b) of 58 mV/dec (RuO₂ b = 91 mV/dec), a charge transfer resistance (R_ct) of 7 Ω (RuO₂ R_ct = 39 Ω), and a faradaic efficiency (FE) of 95% (RuO₂ FE = 91%). Structural changes in the materials could be seen through a stability test in the alkaline electrolyte, and chronopotentiometry over 12 h showed that the derived electrocatalysts and RuO₂ have good stability. Full article