Search Results (14)

National and provincial surveillance of pine wood-boring pests in China is designed to detect damaging taxa, map occurrence, assess risk and loss, and support early warning, zoning and control decisions. Province-scale comparisons of alternative monitoring devices remain rare, especially under the operational conditions required by such programs in climatically and topographically heterogeneous forests. Using data from the 2025–2026 systematic survey of pine wood-boring pests in Yunnan Province, China, we integrated several monitoring datasets to compare baited logs, lure traps, and flight-intercept traps. The harmonized database comprised 2603 standard monitoring subcompartments and 3519 installed sites, including 4080 baited-log piles, 4807 lure-trap units, and 373 flight-intercept traps. Main performance analyses focused on active sites with at least one collection event (570 baited-log sites, 63 flight-intercept sites, and 496 lure-trap sites), whereas installed site summaries were retained to characterize operational coverage. Because the study was observational and the three devices have different sampling mechanisms, we interpreted detection probability as the primary early warning metric, and catch, operational taxon richness, standardized yield, and cost metrics as supporting indicators of diagnostic and operational return. Site-level comparisons were complemented with paired analyses of 21 co-located subcompartments, a more comparable subset defined within county × elevation band × host group strata represented by all three methods, county-clustered regression, and a taxonomic-resolution sensitivity analysis. Lure traps consistently had the highest detection probability (0.73), the greatest cumulative catch (8617 individuals), and the broadest operational taxonomic coverage (45 operational taxa). In county-clustered models, lure traps had higher odds of detection (odds ratio = 11.25, 95% CI: 5.64–22.43) and higher catch rates (incidence rate ratio = 5.97, 95% CI: 2.26–15.76) than baited logs after adjustment for elevation band, host group, and collection effort. The same ranking persisted in the more comparable subset and after exclusion of unresolved family-, subfamily-, genus-, and unknown-level records. Standardized yield peaked at 1500–2200 m. Scenario-based costing showed that lure traps had the lowest cost per captured and resolved captured individual, whereas detection cost estimates were interpreted together with absolute detections and operational taxonomic output. Overall, the results support a tiered surveillance architecture in which lure traps serve as the primary routine early warning tool, baited logs provide targeted complementary information, and flight-intercept traps are reserved mainly for exploratory or faunistic surveys. Full article

The Yellow River Floodplain region of Shandong Province is dominated by silty soils that challenge geotechnical construction. Drilling–Mixing–Jetting (DMJ) Deep Cement Mixing Pile groups have been adopted to improve the geotechnical properties of the soil. This study conducted field tests to evaluate column strength and numerically investigated the effects of area replacement ratio (7.10%, 10.66% and 14.21%) and column spacing. It is observed that the DMJ-integrated columns demonstrate enhanced soil–cement strength in the Yellow River Floodplain region, with sample strengths varying between 2 and 8 MPa. The electrical resistivity of soil–cement shows a strong linear correlation (Pearson’s R > 0.75) with unconfined compressive strength. Settlement reduction ratios range between 32.11% and 94.75% and increase with higher area replacement ratio (ARR) and applied stress but decrease with larger column spacing. Bearing capacity improvement factors are found to be increased with ARR, while column spacing has minimal effect, with values between 423.89 kPa and 431.61 kPa. Lateral displacement decreased with column installation and increasing area replacement ratio (ARR), while the effect of column spacing was confined to depths near the column head. Full article

Amphibians face a global conservation crisis, driven largely by habitat degradation. Effective and practical strategies for habitat restoration are urgently needed, particularly for Critically Endangered species in human-impacted ecosystems. Telmatobius philippii is a species classified as Critically Endangered by the IUCN. Its habitat is restricted to a few thermal springs in the Ascotán salt flat in Chile. A significant portion of one of these springs, V11, dried up in 2005 due to industrial groundwater withdrawals, leading to the loss of natural refuges and population decline. As part of a recovery plan for this spring we implemented a habitat improvement program by installing artificial refuges (clay tiles, bricks, and rock piles) and monitored their use over a two-year period. The results indicated that the refuges, particularly the clay tiles, were utilized by T. philippii at all life stages (larvae, juveniles, and adults). Refuge occupancy increased over time, reaching 75% by the end of the study, and the presence of eggs and early-stage larvae confirmed successful breeding associated with the artificial structures. This demonstrates the positive effect of artificial refuges as a practical tool for the recovery of Telmatobius populations. To our knowledge, this study provides the first documented case of successful habitat enhancement for this threatened group of high Andean amphibians, offering a replicable strategy for conservation in fragile ecosystems. Full article

Screw piles are widely used in infrastructure, such as railways, highways, and ports, etc., owing to their large pile resistance compared to unthreaded piles. While most screw pile research focuses on single pile behavior under rotational installation using torque-capacity correlations. Limited studies investigate group effects under alternative installation methods. In this study, the load-transfer mechanism of screw piles and soil displacement under vertical installation was explored using laboratory model tests combined with digital image correlation techniques. In addition, numerical simulations using the discrete element method were performed. Based on both lab tests and numerical simulation results, it is discovered that the ultimate bearing capacity of a single screw pile was approximately 50% higher than that of a cylindrical pile with the same outer diameter and length. For pile groups, the group effect coefficient of a triple-pile group composed of screw piles was 0.64, while that of cylindrical piles was 0.55. This phenomenon was caused by the unique thread-soil interaction of screw piles. The threads generated greater side resistance and reduced stress concentration at the pile tip compared with cylindrical piles. Moreover, the effects of pile type, pile number, embedment length, pile spacing, and thread pitch on pile resistance and soil displacement were also investigated. The findings in this study revealed the micro–macro correspondence of screw pile performance and can serve as references for pile construction in practice. Full article

First demonstrated in 1942, subcritical and zero-power critical assemblies, also known as piles, are a fundamental tool for research and education at universities. Traditionally, their role has been primarily instructional and for measuring the fundamental properties of neutron diffusion and transport. However, these assemblies could hold potential for modern applications and nuclear research. The Purdue University subcritical pile previously lacked a substantial testing volume, limiting its utility to simple neutron activation experiments for the purpose of undergraduate education. Following the design and addition of a mechanical and electrical testbed, this paper aims to provide an overview of the testbed design and characterize the neutron flux of the rearranged Purdue subcritical pile, justifying its use as a modern scientific instrument. The newly installed 1.5 × 10⁵ cubic-centimeter volume testbed enables a systematic investigation of neutron and gamma effects on materials and the generation of a comprehensive data set with the potential for machine learning applications. The neutron flux throughout the pile is measured using gold-197 and indium-115 foil activation alongside cadmium-covered foils for two-group neutron energy classification. The neutron flux measurements are then used to benchmark a detailed geometrically and materialistically accurate Monte Carlo model using OpenMC 0.15.0 and MCNP 6.3. The experimental measurements reveal that the testbed has a neutron environment with a total neutron flux approaching 9.5 × 10³ n/cm² × s and a thermal flux of 6.5 × 10³ n/cm² × s. This work establishes that the modified Purdue subcritical pile can provide fair neutron and gamma fluxes within a large volume to enable the radiation testing of integral electronic components and can be a versatile research instrument with the potential to support material testing and limited isotope activation, while generating valuable training data sets for machine learning algorithms in nuclear applications. Full article

In offshore pile engineering, the installation of jacked piles generates compaction effects within soil, thus further affecting previously installed adjacent piles. This study proposes a three-dimensional numerical model for pile group installation, soil consolidation, and loading analysis. Subsequently, the effect of pile spacing and pile length-to-diameter ratio on the deformation, internal forces, and vertical bearing capacity of adjacent piles are investigated. The results indicate that with an increase in pile center distance, the peak lateral displacement of the adjacent piles decreases, whereas the peak vertical displacement increases. As the pile length-to-diameter ratio increases, the peak vertical and lateral displacements of the adjacent piles are enhanced. In addition, the peak axial force of the adjacent piles initially decreases and then increases with the penetration depth of the subsequent pile, whereas the peak bending moment initially increases and then decreases. The vertical bearing capacity of the subsequent pile is significantly superior to that of the adjacent piles. Therefore, the effects of pile installation on adjacent piles should be included in pile engineering. The impact of the subsequent pile installation on the bearing capacity of adjacent piles can be significantly reduced by increasing the pile center distance and pile length-to-diameter ratio. The findings provide useful guidance for pile group engineering. Full article

Pile construction projects cause significant time and expense overruns. The pile installation activity is the primary reason for project underperformance and uncertainties. Additionally, the risks associated with pile installation are mostly considered independent in the overall risk management process, leading to inadequate risk assessment and response. However, few studies have evaluated the risks associated with pile installation. Thus, this study aims to establish the risks of the time and cost of pile installation, using an interdependency network model with a particular emphasis on sand and rocky terrain conditions. In addition, this study introduces a new method for establishing a model that considers the interrelationships among risks via a partial least squares structural equation model (PLS-SEM). The research methodology involves assessing the probability and impact of 53 risk factors of pile installation time and cost. Twelve pile construction experts participated in this assessment. Then, a Monte Carlo Simulation was utilized before the data were integrated into the PLS-SEM. The research findings reveal that the site and economic risks indirectly affect the cost of installing pile in sand through construction risks. Also, the risk group comprising site and equipment risks indirectly affects the cost of installing pile in rock through design risks. This study’s findings will help construction organizations to improve time and cost risk assessments for pile installation projects. Full article

Pile groups are frequently employed to reinforce soft soil foundations, while the piling process frequently disturbs the adjacent foundation. The shielding effect, which prevents the transmission of disturbances from pile installation, is indispensable for minimizing engineering disturbances and optimizing pile group construction techniques. However, current research focuses predominantly on characterizing the phenomenon of shielding, with a limited exploration of the mechanism. To eliminate the limitation, a numerical investigation of the shielding mechanism of pile groups in a pile–soil system is performed this study. Using the finite difference program FLAC^3D and the cavity expansion theory, a three-dimensional numerical model of a pile–soil foundation was created. During the sequential penetration of piles, the response characteristics of the soil surrounding the piles were investigated. Displacement field was first investigated to determine the presence of shielding effects in the pile group and then highlighted the effective role of the existing piles in controlling deformation. Furthermore, through a combined analysis of the stress and strain fields during piling, the mechanism of the shielding effect induced by pile construction is proposed, which is attributed to the direct obstruction effect of piles and the “soil arching effect” created by the soil between piles. The former is reflected by the direct barrier of the existing pile to the soil displacement induced via the installation of the new piles. The latter is reflected by the obstruction of soil between two existing piles to the displacement of soil passing through the two existing piles. This research provides a comprehensive understanding of the mechanical behavior of the pile–soil system and has practical implications for controlling disturbances and optimizing construction techniques in piling engineering projects. Full article

A large number of jackup offshore platforms with towers are widely applied in ocean engineering. The dynamic response of the platforms to waves of large wave height is critical, as such waves may cause platform accidents, property damage, and casualties. Therefore, it is important to investigate the coupling effect of jackup offshore platform, towers and seabed foundations under waves of large wave height. In this study, the coupling effect of offshore platforms, tower structures, and seabed foundations under the impact of waves of large wave height was studied via a physical flume model test. The experimental results show that the impact of waves of large wave height on the platforms is significant when the wave is blocked by the platform surface as the water body gathers under the platform surface, causing a pile group effect that results in the onshore piles being subjected to larger pressures than the front ones. The combined action of wave impact and pile leg squeezing force leads to an increase in the pore pressure of the foundation bed near the pile leg, and the soil near the pile leg becomes soft, revealing the mechanism of instability of the offshore platform’s pile foundation under waves of large wave height. The acceleration of the longitudinal movement of the platform increases under waves of large wave height, and the vortex-induced vibration of the platform includes the vibration along the direction of the wave and perpendicular to it. A coupled vibration effect between the tower structure and the platform occurs under waves of large wave height, reducing the vibration of the platform itself. Furthermore, damping members are installed on the tower structure, greatly reducing the natural vibration period and the motion response of the tower structure. This study provides significant enlightenment for the design of offshore platforms with towers to protect against waves of large wave height. Full article

Several studies have been reported in published literature on analytical solutions for a laterally loaded pile installed in a homogeneous single soil layer. However, piles are rarely installed in an ideal homogeneous single soil layer. The present study describes a new continuum-based analysis or energy-based approach for predicting the pile displacement responses subjected to static lateral loads and moments considering the soil non-linearity. This analytical analysis treats the pile as an elastic Euler–Bernoulli beam and the soil as a three-dimensional (3D) continuum in which the non-linear elastic properties are described by a modulus degradation relationship. The principle of virtual work was applied to the energy equation of a pile–soil system in order to obtain the governing differential equation for the pile and soil displacements. An iterative procedure was adopted to solve the equations numerically using a finite difference method (FDM). The pile displacement response was obtained using the software MATLAB R2021a, and the results from the energy-based method were compared with those obtained from the field test data as well as the finite element analysis (FEA) based on the software ANSYS Workbench 2021R1. The present study investigated the effect of explicit incorporation of soil properties and layering through a parametric study in order to understand the importance of predicting appropriate pile displacement responses in a linear elastic soil system. The responses indicated that the effect of soil layers and their thicknesses, pile properties and the variation in soil moduli have a direct impact on the displacements of piles subjected to lateral loading. Hence, a proper emphasis has to be given to account for the soil non-linearity. Considering the effect of soil non-linearity, it is observed that the results obtained from the energy-based method agreed well with the field measured values and those obtained from the FEA. The results indicated a difference of approximately less than 7% between the proposed method and the FEA. The approach presented in this study can be further extended to piles embedded in multi-layered soil strata subjected to the combined action of axial loads, lateral loads and moments. Furthermore, the same approach can be extended to study the response of the soil to group piles. Full article

Extensive numerical and analytical studies exist that focus on the scours around bridge piers with different cross-sections. However, studies addressing the scour around bridge piles are rather limited and not conclusive. Therefore, the most efficient cross-section reducing the local scour around a pile group is experimentally examined herein. Accordingly, comparative scouring of three different shapes, namely, circular, rectangular and lenticular, is investigated by installing a cohesion-less bedding material around scaled bridge piles immersed in clear water. It is also shown that the available pier scour predictive models grossly underestimate the depth of pile scour holes. For example, the pier predictive models underestimate the pile scours hole by more than 50% in the case of square and circular cross-sections. It also transpires from the experimental investigation that the scour hole depth around the square shape pile is significant, around the circular pile is moderate and around the lenticular pile is minimal. Full article

Piles provide a convenient solution for heavy structures, where the foundation soil bearing capacity, or the tolerable settlement may be exceeded due to the applied loads. In cohesionless soils, the two frequently used pile installation methods are driving and drilling (or boring). This paper reviews the results of a large database of pile load tests of driven and drilled piles in cohesionless soils at various locations worldwide. The load test results are compared with the static analysis design method for single piles recommended in the Canadian Foundation Engineering Manual (CFEM) and other codes and standards such as the American Association of State Highway and Transportation Officials, Federal Highway Administration, American Petroleum Institute, Eurocode, and the Naval Facilities Engineering Command. An improved pile design procedure is proposed linking the pile design coefficients $\left(\beta \right)$ and $\left(N_t\right)$ to the friction angle of the soil, rather than employing the generalized soil type grouping scheme previously used in the CFEM. This improvement included in the new version of the CFEM 2021 produces a more unified value of the pile capacity calculated by different designers, reducing the obtained design capacity discrepancies. Full article

Accuracy metrics have been widely used for the evaluation of predictions in machine learning. However, the selection of an appropriate accuracy metric for the evaluation of a specific prediction has not yet been specified. In this study, seven of the most used accuracy metrics in machine learning were summarized, and both their advantages and disadvantages were studied. To achieve this, the acoustic emission data of damage locations were collected from a pile hit test. A backpropagation artificial neural network prediction model for damage locations was trained with acoustic emission data using six different training algorithms, and the prediction accuracies of six algorithms were evaluated using seven different accuracy metrics. Test results showed that the training algorithm of “TRAINGLM” exhibited the best performance for predicting damage locations in deep piles. Subsequently, the artificial neural networks were trained using three different datasets collected from three acoustic emission sensor groups, and the prediction accuracies of three models were evaluated with the seven different accuracy metrics. The test results showed that the dataset collected from the pile body-installed sensors group exhibited the highest accuracy for predicting damage locations in deep piles. Subsequently, the correlations between the seven accuracy metrics and the sensitivity of each accuracy metrics were discussed based on the analysis results. Eventually, a novel selection method for an appropriate accuracy metric to evaluate the accuracy of specific predictions was proposed. This novel method is useful to select an appropriate accuracy metric for wide predictions, especially in the engineering field. Full article

Model tests were carried out in dry silica sand under pile loading and visualizing observation to investigate the behavior of a pile group. The pile group consisted of nine cylindrical model piles of 40 mm in diameter in most tests or three rectangular parallelepiped model piles in the visualizing observation. Pile spacings of 200 mm and 100 mm between pile centers were used in the models. Tactile sensors were installed to measure the pressure distribution in the ground and colored sand layer with particle image velocimetry (PIV) analysis to reveal the ground deformation in addition to strain gauges inside the model piles to investigate the interaction among group piles. The tests results showed that a narrower spacing between piles resulted in a wider affected area of the ground and the interaction was more significant below the tips. Full article