Search Results (379)

This paper investigates the influence of groundwater level fluctuations on the vibration response and isolation performance of saturated soil foundations under moving loads. A coupled model consisting of an overlying elastic layer and a saturated half-space is established, with water level variation simulated by adjusting the elastic layer thickness. Using Biot’s theory and Fourier transforms, the dynamic response is solved analytically and validated numerically via COMSOL6.0 simulations with perfectly matched layers. Results indicate that the groundwater level significantly affects wave propagation: deeper water levels lead to responses resembling an elastic half-space, while rising water levels amplify surface displacement due to wave reflection at the saturation interface. As water levels approach the surface, behavior converges to that of a fully saturated foundation. P-wave resonance at certain water levels reduces isolation effectiveness. Furthermore, isolation performance is sensitive to load frequency, soil permeability, and trench dimensions. These findings offer valuable insights for designing vibration mitigation measures in environments with variable groundwater conditions. Full article

Due to the complexity of impurity removal from the residual film, there is currently no better impurity removal equipment. To improve the screening performance of the residual film mixture, the vibrating screen was designed. In this paper, the key factors A, B, C, and D were identified through mechanical analysis of the mixture (where they represented the screen aperture diameter, vibration amplitude, vibration frequency, and screen mesh inclination angle, respectively). The soil screen rate (Y₁) and screening loss rate (Y₂) were evaluated. And the optimal ranges for these factors were determined by single-factor experiments. Based on the EDEM, the discrete element model was established to simulate the interaction between residual film and soil. And the motion characteristics of the residual film mixture were analyzed within the screen body through a combination of simulation and bench tests. The vibrating screen’s structural parameters were optimized using Box-Behnken experiments. The most suitable combination of settings was as shown below: A = 6.5 mm, B = 25 mm, C = 3.8 Hz, and D = 4°. Following the optimization of these parameters, the screening performance was optimized. Results of bench tests showed that the soil screening rate was 80.33% and the screening loss rate was 19.31%. This study was expected to offer theoretical and simulation-based methods for optimizing the parameters of residual film-soil vibrating screening devices. Full article

This paper introduces a novel 3D simulation framework that integrates the Pipe-in-Pipe (PiP) model with Finite Element Analysis (FEA) using Ansys Parametric Design Language (APDL). This framework is designed to incorporate a 3D building model directly, assessing ground-borne vibrations from metro tunnels and their impact on surrounding structures. The PiP model efficiently calculates displacement fields around tunnels in full-space, applying the resulting fictitious forces to the FEA model, which includes a directly coupled 3D building model. This integration allows for precise simulation of vibration propagation through soil into buildings. A comprehensive verification test confirmed the model’s accuracy and reliability, demonstrating that the hybrid PiP-FEA model achieves significant computational savings-approximately 40% in time and 65% in memory usage-compared to the traditional full 3D FEA model. The results exhibit strong agreement between the PiP-FEA and full FEA models across a frequency range of 1–250 Hz, with less than 1% deviation, highlighting the effectiveness of the PiP-FEA approach in capturing the dynamic behavior of ground-borne vibrations. Additionally, the methodology developed in this paper extends beyond the specific case study presented and shows potential for application to various urban vibration scenarios. While the current validation is limited to numerical comparisons, future work will incorporate field data to further support the framework’s applicability under real metro-induced vibration conditions. Full article

Compacted and degraded soils pose increasing challenges to agricultural practices, necessitating innovative approaches to soil tillage. This paper evaluates the performance of a vibratory-enhanced moldboard plowing system, designed to improve energy efficiency and tillage quality under compacted and moisture-deficient conditions, typical of low-moisture soils. Field experiments were conducted across four distinct Romanian regions with varying soil types and climatic conditions, all characterized by significant compaction and limited soil moisture. The vibratory system, mounted directly on each plow body, employed sinusoidal oscillations generated by a DC moto-vibrator, to reduce soil adhesion and traction force requirements, thereby lowering fuel consumption. Key parameters including fuel consumption, working speed, soil fragmentation, weed incorporation, and traction force were measured and compared with the conventional plowing method. The results showed enhanced soil fragmentation and more effective residue incorporation, along with notable reductions in traction effort and fuel use at optimal oscillation settings. These findings highlight the potential of vibratory tillage to be used as a soil preparation method for compaction-prone areas, improving the soil structure while increasing operational energy efficiency. Full article

To enhance the stability and consistency of topdressing depth during maize fertilization, an inter-row deep fertilizer application unit was designed. Through analysis of the coherence between subsurface pressure and topdressing depth stability obtained from stability performance tests, structural optimizations were implemented on the deep application unit. This resulted in an integrated vibration damping device incorporating a magnetorheological damper (MR damper fertilizer application unit). The MR damper fertilizer application unit was validated through simulation testing. Using an orthogonal experimental design approach, soil bin tests were conducted to identify the preferred parameter ensemble for this unit. Subsequent field trials under these optimized parameters enabled comparative performance evaluation of both fertilizer application units under actual operating conditions. The simulation results indicated that the MR damper fertilizer application unit achieved reductions in the standard deviation of the gauge wheel’s force on the ground by 39.6%, 41.0%, and 44.6% at three distinct operational speeds, respectively. The soil bin tests identified the optimal operational parameters as follows: MR damper current of 0.6 A, vibration damping system spring stiffness of 8 N/mm, and a working speed of 7.2 km/h. Field testing results indicated that, when utilizing the optimal parameters, the MR damper fertilizer application unit achieved a 6.9% improvement in the rate of qualified topdressing depth and a 3.8% reduction in the depth variation coefficient compared to the conventional deep fertilizer application unit. Compared to traditional fertilizer applicators, this study effectively addresses issues of poor fertilization depth uniformity and low qualification rates caused by severe gauge wheel bouncing due to uneven terrain during field operations. Full article

Precision agriculture applies data-driven strategies to manage spatial and temporal variability within fields, aiming to increase productivity while minimizing pressure on natural resources. As interest in smart tillage systems expands, this study explores a central question: Can tillage tools be used to measure soil compaction during regular field operations? To investigate this, vibration data measurements were collected from a cultivator shank in the northeast of Kansas using the AVDAQ system. The test field soils were Reading silt loam and Eudora–Bismarck Grove silt loams. The relationship between shank vibrations, soil moisture (measured by a Hydrosense II soil–water sensor), and soil compaction (measured by a cone penetrometer) was evaluated using machine learning models. Both XGBoost and Random Forest demonstrated strong predictive performance, with Random Forest achieving a slightly higher correlation of 93.8% compared to 93.7% for XGBoost. Statistical analysis confirmed no significant difference between predicted and measured values, validating the accuracy and reliability of both models. Overall, the results demonstrate that combining vibration data with soil moisture data as model inputs enables accurate estimation of soil compaction, providing a foundation for future in situ soil sensing, reduced tillage intensity, and more sustainable cultivation practices. Full article

Elevated railways are a crucial component of railway lines, characterized by their widespread distribution, simple structure, and low cost, while actively promoting local economic development. However, they also cause significant ground vibrations when trains pass. Similarly, considerable vibration levels are transmitted to the subgrade and surrounding structures when trains operate on viaducts within the Loess Plateau region. However, research on mitigating these vibration effects remains relatively scarce. This study focused on the impacts of such vibrations on surrounding buildings and stratum structures and evaluated the effectiveness of a vibration isolation trench in mitigating these effects. Time frequency domain analysis of ground vibrations during train passage revealed that the characteristic frequency of the train-induced pulse excitation in the track structure had a pronounced peak in the spectrum curve. The introduction of a vibration isolation trench effectively blocked the propagation of vibration waves in the soil, reduced soil vibration, and significantly lowered the peak value in the spectrum. Numerical simulations were employed to analyze the elliptical polarization dispersion characteristics of surface wave propagation with the vibration isolation trench in place, confirming the effective damping performance of the trench. These findings could offer a valuable reference for high-speed railway vibration isolation and significantly advance the application of surface wave theory in high-speed railway technology. Full article

The compaction quality of soil–rock mixture (SRM) subgrades critically influences infrastructure stability, but conventional settlement difference methods exhibit high spatial sampling bias (error > 15% in heterogeneous zones) and fail to characterize the overall compaction quality. These limitations lead to under-compaction (porosity > 25%) or over-compaction (aggregate fragmentation rate > 40%), highlighting the need for real-time monitoring. This study develops an intelligent compaction system integrating (1) vibration acceleration sensors (PCB 356A16, ±50 g range) for compaction meter value (CMV) acquisition; (2) near-infrared (NIR) moisture meters (NDC CM710E, 1300–2500 nm wavelength) for real-time moisture monitoring (sampling rate 10 Hz); and (3) an embedded edge-computing module (NVIDIA Jetson Nano) for Python-based data fusion (FFT harmonic analysis + moisture correction) with 50 ms processing latency. Field validation on Linlin Expressway shows that the system meets JTG 3430-2020 standards, with the compaction qualification rate reaching 98% (vs. 82% for conventional methods) and 97.6% anomaly detection accuracy. This is the first system integrating NIR moisture correction (R² = 0.96 vs. oven-drying) with CMV harmonic analysis, reducing measurement error by 40% compared to conventional ICT (Bomag ECO Plus). It provides a digital solution for SRM subgrade quality control, enhancing construction efficiency and durability. Full article

The growing concerns over nuclear power plant safety in the wake of extreme impact events have highlighted the need for containment structures with superior resistance to large commercial aircraft strikes. Conventional reinforced concrete containment has shown limitations in withstanding high-mass and high-velocity impacts, posing potential risks to structural integrity and operational safety. Addressing this challenge, this study focuses on the dynamic impact resistance and vibration behavior of steel–ultra-high-performance concrete (S-UHPC) composite containment, aiming to enhance nuclear facility resilience under beyond-design-basis aircraft impact scenarios. Validated finite element models in LS-DYNA were developed to simulate impacts from four representative large commercial aircraft types, considering variations in wall and steel plate thicknesses, UHPC grades, and soil–structure interaction conditions. Unlike existing studies that often focus on isolated parameters, this work conducts a systematic parametric analysis integrating multiple aircraft types, structural configurations, and foundation conditions, providing comprehensive insights into both global deformation and high-frequency vibration behavior. Comparative analyses with conventional reinforced concrete containment were performed, and floor response spectra were evaluated to quantify high-frequency vibration characteristics under different site conditions. The results show that S-UHPC containment reduces peak displacement by up to ~24% compared to reinforced concrete of the same thickness while effectively localizing core damage without through-thickness failure. In addition, aircraft impacts predominantly excite 90–125 Hz vibrations, with soft soil conditions amplifying acceleration responses by more than four times, underscoring the necessity of site-specific dynamic analysis in nuclear containment and equipment design. Full article

To mitigate the high stubble rates (root residue rates) and plant damage associated with the current mechanized harvesting of Shanghai Green (Brassica rapa subsp. chinensis), this study developed and optimized a novel soil loosening and root lifting device. A theoretical dynamic model was first established to analyze the device’s operational principles. Subsequently, a coupled multi-body dynamics and discrete element method (RecurDyn-EDEM) model was established to simulate the complex interactions between the device, soil, and plant roots. Response surface methodology was employed to optimize key operational parameters: walking speed, loosening depth, and vibration frequency. The simulation-based optimization was validated by field tests. The optimal parameters were identified as a walking speed of 0.137 m/s, a loosening depth of 34.5 mm, and a vibration frequency of 1.34 Hz, under which the Shanghai Green pulling force was 35.41 N, yielding optimal extraction performance. Field tests conducted under these optimal conditions demonstrated excellent performance, achieving a qualified plant posture rate of 87.5% and a low damage rate of 7.5%. This research provides a robust design and validated operational parameters, offering significant technical support for the development of low-loss harvesting equipment for leafy vegetables. Full article

Vertical low-permeability barriers are widely used to improve the stability and seepage resistance of flood embankments. The present study evaluates three barrier technologies—vibrating beam slurry walls (VBSWs), deep soil mixing (DSM), and low-pressure grout injection (LPG)—through a series of consolidated drained triaxial tests and permeability coefficient tests on soil samples collected from the sites where different barrier installation technologies were used. All three barrier installation methods produced substantial improvements in both mechanical and hydraulic performance: the effective angle of internal friction (φ′) increased by 3–6° in samples with a plasticity index near 3.5%, and coefficients of permeability dropped from 10⁻⁸–10⁻⁷ m/s in untreated soils to below 10⁻⁹ m/s in treated specimens. The key finding of the study is that the barrier performance varies by the technology and the soil type. According to the result, DSM is the most effective technology used in clay-rich soils (φ′ increased up to 4°); LPG achieved the lowest permeability (7 × 10⁻¹¹ m/s) in granular soils; and VBSWs balanced strength and impermeability, most effective in silty sands. Flow-pump tests further demonstrated that treated soils required much longer to stabilize under a constant flow rate and could sustain higher hydraulic gradients before reaching equilibrium. These findings show the importance of matching barrier technology to soil plasticity and liquidity characteristics and highlight saturation as essential for reliable laboratory evaluation. The results provide a scientific basis for selecting and designing vertical barriers in flood-preventing infrastructure, offering performance benchmarks for improving hydraulic and geotechnical structures. Full article

Seismic response analysis of underground structures at coral sand sites is a critical component in ensuring the structural safety of island reef engineering. Current experimental studies in this field have primarily focused on unidirectional seismic excitation. To investigate the seismic response differences under multidirectional seismic loading, this study designed a series of shaking table tests under unidirectional, bidirectional, and triaxial loading schemes. The seismic responses of underground structures and coral sand foundations were compared under different loading conditions, including boundary effects, ground and structural accelerations, Fourier spectra, and structural strains. The results indicate that the soil–structure system exhibits responses in the non-excitation directions during the shaking table tests. Compared to the excitation direction, boundary effects are more pronounced in the non-excitation directions, with vibrations in these directions primarily concentrated in the high-frequency range (16–20 Hz). The ground acceleration amplification factors in the X-, Y-, and Z-directions in different loading directions are 0.9–1.3, 1.4–2, and 3.4–3.7, respectively, showing significant differences. Under triaxial loading, the peak strain in the underground structure is significantly higher than that under unidirectional loading. Full article

This study investigates the mechanisms of gas-containing tectonic coal outbursts by modeling tectonic coal and gas as analogous to soil and pore water. Analytical methods from soil mechanics, specifically those related to quicksand and seismic liquefaction, are employed to classify these outbursts into two types: “quicksand type” and “fluidization type.” Their formation mechanisms are elucidated based on a fracture network model and a one-dimensional seepage failure criterion developed for tectonic coal. The findings indicate that “quicksand type” outbursts result from the continuous detachment of tectonic coal slices within the pressure relief zone under gas seepage pressure. The thickness-to-radius ratio of these coal slices increases with rising gas pressure but decreases with increasing coal strength and normal geostress. A larger thickness-to-radius ratio signifies a more pronounced granular characteristic and accelerates the development of coal and gas outbursts. “Fluidization type” outbursts occur when the effective stress drops to zero, resulting in a complete loss of coal strength. These outbursts represent a specific case of “quicksand type” outbursts and can be triggered by vibrations. The susceptibility of tectonic coal to outbursts is attributed to its low mechanical strength and the presence of dense fractures, which increase the acting area of seepage pressure and, consequently, raise the overall seepage force. According to this analysis, the depth of outburst cavities is generally less than the width of the pressure relief zone, which can result in delayed outbursts. This study enhances the understanding of quicksand and seismic liquefaction theories in soil mechanics and provides valuable guidance for predicting and mitigating coal and gas outbursts. Full article

This study presents an advanced simulation-based methodology for evaluating the dynamic vibrational behavior of the operator–vehicle assembly in autonomous electric agricultural tractors. Using the TE-0 electric tractor as the experimental platform, the research is structured into three integrated stages. In the first stage, a seated anthropometric virtual model of the human operator is developed based on experimental data and biomechanical validation. The second stage involves a detailed modal analysis of the TE-0 electric tractor using Altair Sim Solid, with the objective of determining the natural frequencies and vibration modes in the [0–80] Hz range, in compliance with ISO 2631-1. This analysis captures both the structural-induced frequencies—associated with the chassis, wheelbase, and metallic frame—and the operational-induced frequencies, influenced by the velocity and terrain profile. Subsequently, the modal analysis of the “Grammer Cabin Seat” is conducted to assess its dynamic response and identify critical vibration modes, highlighting how the seat behaves under vibrational stimuli from the tractor and terrain. The third stage extends the analysis to the virtual operator model seated on the tractor seat, investigating the biomechanical response of the human body and the operator–seat–vehicle interaction during simulated motion. Simulations were carried out using SolidWorks 2023 and Altair Sim Solid over a frequency range of [0–80] Hz, corresponding to operation on unprocessed soil covered with grass, at a constant forward speed of 7 km/h. The results reveal critical resonance modes and vibration transmission paths that may impact operator health, comfort, and system performance. The research contributes to the development of safer, more ergonomic, and sustainable autonomous agricultural transport systems. By simulating real-world operation scenarios and integrating a rigorously validated experimental protocol—including vibration data acquisition, biomechanical modeling, and multi-stage modal analysis—this study demonstrates the importance of advanced modeling in optimizing system-level performance, minimizing harmful vibrations, and supporting the transition toward resilient and eco-efficient electric tractor platforms in smart agricultural mobility. Full article

Aiming at key issues in harvesting film-covered potatoes in hilly and mountainous areas—incomplete residual film collection, poor potato–soil separation, and high damage from potato-collecting devices—this study developed a crawler self-propelled potato harvester suitable for these regions. This study first expounds the overall structure and working principle of the potato harvester and then conducts principal analysis and structural design for key components (film-collecting device, digging device, primary conveying and separating device, secondary conveying and separating device, and intelligent potato-collecting device) from the perspectives of material force and movement. Finally, field performance tests were carried out in Huangzhong County, Xining City, Qinghai Province. The test results show that the machine can achieve an operation effect with a potato harvest loss rate of 2.4%, a potato damage rate of 1.4%, an impurity content rate of 2.8%, a skin-breaking rate of 2.7%, and a residual film cleaning rate of 89.6%, meeting the potato harvesting needs of this region. The lightweight self-propelled crawler potato harvester designed in this paper can realize functions such as residual film collection, potato–soil vibration separation, manual auxiliary sorting, and intelligent potato boxing, providing technical and equipment references for the harvesting of film-covered potatoes in complex terrain areas. Full article