Search Results (489)

Bandpass filters based on through-silicon-via (TSV) interposers offer advantages such as compact footprint, excellent radio frequency (RF) performance, simplified processing, and low cost. However, as power densities in three-dimensional (3D) integrated circuits continue to rise, thermal management has become a critical performance bottleneck. In this work, we present a TSV-based bandpass filter design where the TSVs feature annular Cu conductors with carbon nanotube (CNT) cores. The annular Cu structure provides the required vertical electrical connectivity, while the high-thermal-conductivity CNT core facilitates inter-layer heat dissipation. RF simulations confirm that the RF characteristics of the filter remain comparable to those of filters based on conventional TSVs with Cu-pillar conductors or TSVs with annular Cu conductors and polymer cores such as benzocyclobutene (BCB). In addition, multiphysics simulations demonstrate that the proposed filter exhibits a maximum steady-state temperature of only 89.1 °C with a 5 W constant heat source attached to the interposer surface and a heat sink at the bottom side, presenting an efficient reduction compared to the other two types. The filter also shows reduced thermally induced surface deformation, confirming the thermal benefits of the CNT cores. Furthermore, comprehensive parametric analyses involving the influences of critical TSV structural parameters on the TSV-based capacitors and inductors are performed, providing guidelines for customized filter design. We believe the proposed design highlights a promising pathway for addressing the thermal management challenges in high-density RF integrated microsystems. Full article

Marine propulsion shaft alignment is affected by bearing offsets, hull deformation, thermal growth, and condition-dependent propeller and gear loads. An alignment scheme optimized for a single condition may therefore lead to unbalanced bearing reactions or excessive shaft-line deformation in service. To improve multi-condition alignment performance while reducing the reliance on repeated direct finite element evaluations during optimization, this study proposes a hybrid surrogate-assisted multi-objective optimization framework for a container-ship propulsion shafting system. A beam finite element model based on Euler–Bernoulli theory is established and numerically checked using jack-up calculations. Cold static, hot operating, and zero-pitch conditions are considered. Bearing-load uniformity, maximum coupling vertical offset, and maximum shaft slope are selected as objectives. According to response characteristics, an extremely randomized trees model is used for the nonlinear load-uniformity response, whereas response surface models are used for the smoother coupling-offset and shaft-slope responses. The Pareto front is obtained using multi-objective particle swarm optimization, and a compromise scheme is selected using entropy-weighted TOPSIS. For the investigated case, the preferred scheme reduces the three objectives by 44.36%, 38.62%, and 8.65%, respectively, relative to the pre-optimization scheme, and finite element recalculation gives prediction deviations below 5%. The proposed framework provides a practical reference for propulsion shaft alignment optimization under operating conditions. Full article

Optimizing the structural stability of foundations is challenging in modern geotechnical engineering. This study investigated the mechanism of geocell-reinforced foundations through discrete element modeling based on transparent soil model tests. A three-dimensional particle flow code (PFC^3D) model was developed to investigate the micromechanical soil–geocell interactions in both unreinforced and geocell-reinforced foundations under strip loading. Particle displacement, contact force distribution, and structural deformation within the foundation system were analyzed to quantify the performance of geocell reinforcement. The results show that geocell inclusion enhances structural performance by 2.1 times compared to an unreinforced foundation, increasing the bearing capacity from 60.6 to 126.8 kPa at a defined bearing capacity criterion. The geocell walls act as rigid physical boundaries that microscopically intercept the lateral migration and horizontal extrusion of soil particles. The kinematic trajectories of soil particles beneath the loading plate are forced into a downward realignment, decreasing the displacement vector rotation angle from 42° in the unreinforced soil to 27° in the reinforced soil and effectively mitigating the heave of adjacent surfaces. Furthermore, the quasi-rigid three-dimensional network completely interrupts the continuous steep contact force chains inherent in unreinforced foundations. Concentrated vertical stresses are converted into horizontal components through interfacial friction and mechanical interlocking, resulting in the lateral redistribution of the applied load by a distance of approximately 0.06 m. The geocell–soil composite considered as a flexible raft foundation extends load dispersion and reduces average subsoil pressure. A coupled tension and compression stress state in the horizontal plane is developed within the geocell structure. Forces are channeled along rigid paths by elevated bending moments and stress concentrations at the cell junctions. These findings provide micromechanical insights into the performance of geocell-reinforced-foundation systems. Full article

Remote-sensing land surface deformation (LSD) is a powerful and effective approach for investigating regional alpine permafrost variations. However, alpine permafrost is often distributed in areas characterized by earthquakes, and the LSD of alpine permafrost is potentially contaminated or diminished by earthquake-related LSD. Therefore, this study aimed to derive the effective LSD in the alpine permafrost of the Source Area Yellow River (SAYR) by removing LSD originating from the M_w 7.4 Maduo earthquake in 2021-05-22 and analyzing the spatiotemporal variations in LSD during 2017–2024. Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) was used to obtain the initial LSD time series from Sentinel-1 images acquired during 2017–2024. The LSD of the M_w 7.4 Maduo earthquake, its aftershocks and the post-seismic relaxation in SAYR was simulated separately by considering its temporal process and removed from the LSD time series in SAYR. The final LSD was validated against in situ Global Navigation Satellite System (GNSS) measurements, and the spatiotemporal variations in LSD in SAYAR were subsequently analyzed. The study found the following: (1) the removal of the earthquake-related LSD was successful both spatially and temporally and the final LSD has mean absolute error (MAE) of 3.22 mm and root mean squared error (RMSE) of 3.92 mm; (2) during 2017–2024, the vertical LSD in SAYR was mostly −8–8 mm/y; (3) soil moisture determined the spatial distribution of the LSD direction in SAYR as a result of local drainage conditions, air temperature, precipitation and snow melt. This study demonstrated the necessity of removing the earthquake-related LSD when investigating the alpine permafrost LSD in tectonically active areas. The strategy adopted in this study serves as a technical reference for future investigations of this kind. The findings in this study provide insight for a thorough understanding of permafrost evolution on the Tibetan Plateau in the context of climate change. Full article

Ground deformation monitoring is critical for safety and environmental management in modern mining. Active mining sites are highly exposed to terrain instabilities and subsidence, risking infrastructure integrity, disrupting operations, and posing hazards to communities. In this context, Differential Synthetic Aperture Radar Interferometry (DInSAR) techniques provide an effective and non-invasive tool capable of detecting millimetric surface displacements. This study implements the Small Baseline Subset (SBAS) technique through an open-source workflow based on the Python package hyp3_sbas, enabling semi-automated and reproducible interferometric processing by combining HyP3 with MintPy. The workflow is applied to the Björkdal gold mine (Sweden), a pilot site of the Horizon Europe XTRACT project focused on enhancing resilience in critical raw material supply chains. Integrating Sentinel-1 viewing geometries resolves the true vertical deformation field, yielding an overall mean velocity of −3.99 mm/year across the mining complex, with significant displacement rates concentrated below the 25th percentile (Q1) at −11.07 mm/year. Sector-specific analysis reveals localised subsidence accelerating over underground footprints and tailings storage facilities (mean velocities of −6.56 and −3.98 mm/year; Q1 thresholds near −13.00 mm/year), contrasting with the geomechanical stability observed at the open-pit area (mean: −0.45 mm/year). The proposed open-source framework shows strong potential for operational satellite-based monitoring, supporting predictive maintenance and early-warning strategies for risk management in mining environments while simplifying and standardising the interferometric processing workflow. Full article

Accurate monitoring of mining-induced three-dimensional surface deformation is critical for safety and environmental protection. Conventional InSAR often loses coherence in high-deformation areas and provides only one-dimensional measurements, while the Probability Integral Model (PIM) suffers from low accuracy at subsidence edges, caused by premature numerical convergence of its error-function-based mathematical formulation—the model prediction rapidly drops to zero and fails to capture subtle real-world deformations in marginal zones. This study developed a fusion method integrating multi-source InSAR (Sentinel-1A and SAOCOM), PIM, and the Covariance Matrix Adaptation Evolution Strategy (CMA-ES). Applied in the Yinying Mining Area, Shanxi Province, the approach combined ascending and descending SAR data processed via SBAS-InSAR, used CMA-ES to optimize PIM parameter inversion, and employed a zonal fusion strategy to reconstruct complete deformation fields. The method demonstrated substantial improvement in monitoring accuracy, with mean absolute errors in the vertical, north–south, and east–west directions reduced by more than 86% compared with the standalone PIM model in edge zones. The fusion approach effectively captured both large-magnitude center deformations and subtle edge displacements. Multi-source data fusion with intelligent optimization algorithms significantly enhances the accuracy of 3D deformation monitoring in mining areas, providing reliable technical support for safety management and environmental protection. Full article

Determining the safe thickness of a boundary crown pillar is critical during the transition from open-pit to underground mining, as it directly affects both mining safety and resource recovery. Crown pillar instability is commonly associated with asymmetric stress redistribution, nonuniform deformation, and progressive plastic failure. In this study, the Kumusayi Li-Nb-Ta mine in Xinjiang, China, was selected as an engineering case to optimize the boundary crown pillar thickness and evaluate its deformation characteristics. Four theoretical methods, namely the load transfer intersection method, span-to-thickness ratio method, simplified structural beam method, and Rubeneeite formula method, were first used to determine the feasible thickness range. The calculated thicknesses were 19.99, 14.00, 29.81, and 10.41 m, respectively, yielding an engineering design interval of 14.00–29.81 m. Based on this interval, four thickness schemes of 15, 20, 25, and 30 m were evaluated using FLAC3D simulations in terms of stress redistribution, displacement evolution, surface movement, plastic-zone development, and deformation symmetry. The results show that the 15 m pillar exhibits pronounced stress concentration, asymmetric deformation, and through-going plastic failure, indicating insufficient stability. Although the 20 m pillar improves the load-bearing capacity, a potential connected failure path remains. At 25 m, the high-stress zone becomes localized, the plastic zone no longer penetrates the pillar, and the maximum vertical displacement decreases by approximately 27.0% compared with the 15 m scheme. Increasing the thickness to 30 m provides limited additional improvement, with less than a 2% reduction in maximum vertical displacement compared with the 25 m scheme. Physical similarity model tests further confirm that a 20.8 cm model pillar, corresponding to a 25 m prototype pillar, effectively prevents through-going cracking and overall slope sliding. Therefore, a 25 m boundary crown pillar is recommended for the Kumusayi mine. Full article

With the growing scarcity of surface space, underground development has become essential for expanding human living space. Among various tunneling methods, pipe jacking stands out due to its economic advantages and minimal environmental impact. Recently, vertical pipe jacking has been explored as an innovative technique for constructing shafts that connect horizontal tunnels to the ground surface. However, the evolution of jacking force during vertical pipe jacking with increasing jacking distance remains poorly understood. Understanding this evolution is critical for selecting jacking equipment, designing the horizontal tunnel lining against reaction forces, and preventing construction failures. Unlike horizontal pipe jacking where self-weight is negligible, the proposed model reveals that in vertical pipe jacking the self-weight of the pipe and machine above the excavation face increases with jacking distance while the overburden pressure decreases, resulting in a parabolic-like jacking force trend—a novel finding not reported in previous pipe jacking literature. This paper proposes theoretical formulas to quantify the three components constituting the jacking force: face resistance at the cutting head, frictional resistance along the pipe surface, and the dead weight of the machine and pipe above. The influence of jacking distance on each component is systematically analyzed. Parametric studies under standard and varied conditions reveal that under standard conditions, jacking force follows a parabolic trend—rapid initial increase, followed by slower growth, and eventually a slight decrease. The maximum jacking force consistently occurs at L = L₀ − 1 m, identifying the most unfavorable construction stage where special attention to tunnel lining deformation is required. Increasing outer diameter transitions the force curve from quasi-parabolic to “half diamond” shape, while doubling the friction coefficient approximately doubles the jacking force. These findings provide practical guidelines for vertical pipe jacking design and construction, including equipment capacity selection, friction reduction strategies, and monitoring priorities. Full article

Comprehensive mechanized solid backfilling technology exhibits significant advantages in solid waste disposal, “three-under” coal mining, and dynamic disaster control. However, its large-scale application is constrained by low production efficiency, high unit production cost, and high labor intensity. Therefore, industrial upgrading through intelligent technologies is urgently required. In this study, methods including literature review, theoretical analysis, and field measurements are employed to propose three backfilling modes. The configurations of the six core subsystems under each mode are systematically summarized, and the core definition of an intelligent backfilling mine is established. Furthermore, a key technology framework for intelligent backfill mining is developed, based on PLC control and PID algorithms, with a closed-loop architecture centered on “perception–decision–execution.” Engineering applications demonstrate that the surface gangue intelligent pretreatment system achieves functions including automatic vehicle washing, intelligent dust suppression spraying at discharge points, dynamic metering during conveying, and adaptive adjustment of feeding systems. The intelligent surface-to-underground coal gangue vertical feeding system enables full silo alarm and level regulation. The underground jigging intelligent separation system realizes intelligent jigging ratio adjustment, intelligent bed layer measurement and control, and intelligent air volume regulation, with the coal content in gangue discharge maintained below 4%. At the working face, the intelligent solid backfilling system doubles monthly coal output, boosts backfilling efficiency by 50%, and cuts the workforce by 8–10 workers. The intelligent backfilling effectiveness monitoring system operates stably, with a working face weighting factor of 1.12 and precise ground deformation control within Grade I limits. Full article

Surface rock movement can lead to geological or environmental problems such as surface subsidence, ground fissure development, and deformation of engineering structures, and its evolution process exhibits significant spatiotemporal heterogeneity. Therefore, conducting high-precision, spatiotemporally continuous monitoring of surface deformation is of great significance for revealing subsidence mechanisms, assessing potential risks, and guiding disaster reduction decisions. GNSS and InSAR have become mainstream methods for monitoring surface deformation, but they still have limitations in terms of spatial sparsity, 3D deformation inversion capability, and data gaps in areas of strong deformation. To address these issues, this paper takes the Jinchuan copper-nickel mine’s No. 2 mining area as the research object and comprehensively utilizes multi-source monitoring data from GNSS and InSAR to construct a joint inversion model of the surface 3D deformation field based on posterior variance component estimation, achieving adaptive optimization of weight allocation and collaborative solution of 3D deformation. To address the issue of InSAR decorrelation in areas of strong deformation, which leads to missing deformation information, a fitting and estimation approach was applied to supplement six decorrelated points that spatially coincide with GNSS stations. These points are located in key deformation areas, and their reconstruction effectively improves the completeness and reliability of the deformation field in critical regions. Based on this, an automated solution process for the fusion model is implemented using MATLAB R2022b, and the joint inversion yields spatiotemporally continuous 3D deformation fields in the northward, eastward, and vertical directions. The results show that compared with traditional monitoring methods, the proposed fusion model exhibits higher inversion accuracy and stability under different InSAR technology conditions, effectively suppressing the impact of single data source errors on the overall solution results. Among them, SBAS-InSAR shows slightly higher accuracy in the vertical direction, while PS-InSAR achieves higher accuracy in the planar direction, as indicated by lower RMSE and MAE values. The research results improve the accuracy and reliability of surface deformation monitoring in mining areas, providing important technical support for safe mining and refined management. Full article

Deformation monitoring of bridges is essential to ensure the structural integrity and serviceability of these critical civil infrastructures. In this context, geodetic measurements using total stations and 3D terrestrial laser scanning (TLS) surveys can provide accurate and reliable data. Multitemporal geodetic observations from total stations enable the tracking of displacements at discrete points, whereas TLS surveys allow for the extension of deformation analysis to entire surfaces. Both techniques can achieve comparable millimeter-level precision. These methods were applied to monitor the deformation of the Ponte della Costituzione (PdC), the most recent pedestrian arch bridge spanning the Grand Canal in Venice (Italy). A total station was used to measure the displacements of six control points installed on structurally significant locations of the bridge. Between 3 October 2023 and 2 February 2026, 28 multitemporal measurement campaigns were conducted. In addition, four TLS surveys, using two different laser scanners, were carried out on 1 August 2025 and 2 February 2026, in order to capture conditions corresponding to maximum annual thermal deformation. The results derived from geodetic measurements reveal a strong correlation among: (i) variations in the distance between the abutments (on the order of 6–7 mm); (ii) vertical displacements of the central upper points of the arch (ranging from 9 to 12 cm); and (iii) fluctuations in ambient temperature. TLS data highlighted a spatially homogeneous deformation pattern extending from the crown of the arch to the abutments, demonstrating that longitudinal displacements affect the entire lateral structure. Mid-term deformation analysis over the two-year period from 6 February 2024 to 2 February 2026 indicates displacement rates of approximately 1.4 mm/year for increasing separation between the abutments and 16.2 mm/year for the decrease in elevation of the central arch point. However, these trends are significantly influenced by environmental temperature variations, as evidenced by an estimated temperature change rate of −3.5 °C/year over the same period. Therefore, continued deformation monitoring of the PdC bridge is recommended in the coming years, particularly in light of ongoing climate change and the associated increase in temperature variability. Full article

Land subsidence is an important challenge faced by coastal cities under rapid urban development. This study focuses on the Haikou–Laocheng area and conducts time-series monitoring of land subsidence using PS-InSAR and SBAS-InSAR based on 42 Sentinel-1 SAR scenes acquired from April 2023 to April 2025, thereby deriving the spatial distribution of cumulative subsidence rates and the evolution patterns of multi-temporal cumulative subsidence. Because only ascending-orbit Sentinel-1 data were used, the reported deformation values are vertical-projected estimates converted from line-of-sight (LOS) displacement under the assumption that horizontal motion is negligible. The reliability of the monitoring results is evaluated through cross-validation between the two methods, assessing their inter-method consistency. The results indicate that the study area is dominated by slight subsidence, with vertical-projected subsidence rates mainly ranging from −6 to 3.7 mm/y, while a few uplift points are locally observed, forming an overall “stable with localized anomalies” deformation pattern. PS-InSAR and SBAS-InSAR show good consistency in overall trends, and both identify a pronounced subsidence bowl in the southwestern part of the study area, where the peak vertical-projected subsidence rates reach −25.1 mm/y and −35.1 mm/y, respectively, with outward banded attenuation. The results suggest that land subsidence in the study area is influenced by both natural factors and human activities. Specifically, rainfall shows a non-synchronous, stage-wise modulation relationship with subsidence evolution, and most high-subsidence zones are distributed in impervious surfaces such as built-up land and transportation corridors, or in low-elevation areas such as farmland. In terms of geological factors, thick, highly compressible soft soils are the primary geological control on the continued development of subsidence. These findings can provide scientific references for the prevention and control of abnormal subsidence and for urban planning and development in the Haikou–Laocheng area. The strengthened discussion clarifies the research gap, planning significance, and limitations of applying dual time-series InSAR in a data-scarce tropical coastal soft-soil setting. Full article

This study investigates vertical surface displacements in an area previously impacted by extensive underground hard coal extraction, specifically focusing on the closed “Kazimierz-Juliusz” mine in the Upper Silesian Coal Basin (Poland). The cessation of mining operations and formal decommissioning do not necessarily signify the termination of ground instability; rather, the discontinuation of mine water pumping triggers a progressive groundwater rebound within the rock mass. This hydrogeological shift leads to a redistribution of stresses in the geological structure, inducing deformation processes that manifest as surface uplift. This research aims to characterize the temporal evolution and magnitude of post-closure surface elevation changes by integrating satellite radar interferometry with conventional geodetic surveys. The analysis, spanning a 28-month observation period, utilizes both Persistent Scatterer Interferometry (PSInSAR) and European Ground Motion Service (EGMS) data, complemented by precise geometric leveling. The results reveal a low-magnitude deformation process, with detected uplift rates reaching approximately 1 cm/year. The synergistic integration of InSAR-based monitoring and classical geodesy allowed for robust cross-validation, significantly enhancing the reliability of the findings both qualitatively and quantitatively. Full article

Planetary exploration has increasingly relied on mobile robots known as rovers to support space development. Among various locomotion systems, legged mechanisms have attracted attention as a promising approach for achieving high mobility on rough terrain. However, the surfaces of extraterrestrial bodies such as the Moon and Mars are covered with loose regolith that easily deforms under external forces. As a result, legged rovers tend to disturb the ground surface and experience slippage due to leg-induced loading. To address this issue, a previous study proposed a novel walking method in which the rover’s leg applies vibration to the soil before stepping to compact it. Experiments confirmed that this vibration increases the soil’s bearing capacity, defined as its resistance to vertical loading. This increase is attributed to improvements in soil density and particle interconnectivity, which enhance soil shear strength. In this study, the relationship between the bearing capacity of vibration-compacted soil and its shear strength is investigated through experiments. The results reveal a clear correlation between these parameters, indicating that the bearing capacity of vibration-compacted soil can be estimated from shear strength measurements. Full article

Tunnel construction in soft soil environments involves significant geological and hydraulic uncertainty, particularly where permeable sandy interlayers within soft clay are prone to seepage-induced instability and excessive settlement. Although hydraulic–mechanical coupling is widely recognized, the spatial variability of key soil parameters (e.g., permeability and elastic modulus) is often inadequately represented, limiting quantitative evaluation of heterogeneous ground effects on construction-induced deformation. In this study, statistical analyses of site investigation and monitoring data are conducted to characterize parameter distributions and transverse settlement trough morphology, supporting model validation. A fluid–solid hydro-mechanical coupled numerical model in ABAQUS demonstrates that groundwater flow increases maximum surface settlement from 3.18 cm to 3.58 cm, confirming the significance of hydraulic coupling. To quantify spatial variability effects, a stochastic finite element framework based on random field theory is developed, showing that variations in vertical correlation length influence both the mean and dispersion of maximum settlement. Specifically, under a settlement control threshold of 40 mm, the failure probability decreases from 24.21% to 1.01% as the vertical correlation length increases from 1.5 m to 6 m. Finally, an engineering-oriented risk assessment framework is established using settlement trough area as the core loss indicator; its lognormal distribution is verified, and failure probability and reliability indices are integrated with code-based thresholds to evaluate construction risk under different scenarios, with the resulting risk levels ranging from Relatively High (Level III) to Moderate (Level II). Full article