Soil Compression Research Articles

К вопросу деформационно-энергетической оценки состояния почвы при обработке

Soil is greatly affected with working parts of agricultural machines and implements during agrotechnical operations of mechanical tillage. Technical means taking part in agricultural production such as wheeled and tracked propulsors of tractors, combines, trailers and other cause an acting deforming load on soil. Any type of soil deformation is carried out using a certain amount of expended energy, therefore the process of changing the properties of the soil when exposed to deformers is associated with giving it a certain energy level. In this case, as the energy costs associated with the transition of soil from one state to another, one should take not the dissipated energy of the working body acting on the soil, but the energy absorbed by the soil, since it is this part of the energy that determines the transition of the soil from one state to another. In this regard, it is proposed to assess the stress-strain and energy state of the soil on the basis of a mechanical model of its compression. The article presents some results of theoretical studies aimed at developing such a model. The mechanical model of soil compression characterizes its stress-strain state at all stages of deformation under the energetic influence of working bodies and running systems of agricultural machinery from the moment of the onset of deformation until destruction. For this purpose, the mechanical model of soil compression sequentially and in parallel includes elastic and viscous elements in which stress redistribution occurs when the rate of application of the deforming load changes, which corresponds to a real change in the stress-strain state of the soil under specific conditions.

Exploring Resistance Reduction of Subsoiling Through Sandfish (Scincus scincus) Inspired Sinusoidal Locomotion

Highlights Biomimetic design, inspired by sandfish locomotion, decreased subsoiling resistance. Penetration tests and simulations showed bioinspired tines outperforming traditional ones in resistance reduction. DEM-MBD co-simulation effectively modeled the sandfish's movement, revealing the mechanisms of soil interactions. Simulations confirmed that sinusoidal subsoiler movement significantly reduced soil resistance. Abstract. This study addresses the issue of high resistance and low efficiency in subsoiling operations by employing a novel method inspired by the unique locomotion of the sandfish (scincus scincus), aimed at reducing forward resistance. The unparalleled adaptability of the sandfish in navigating granular media, such as desert sand, offers valuable insights for enhancing agricultural machinery. This research employs sandfish’s movement principles to propose innovative strategies for improving subsoiling efficiency. A sandfish inspired prototype, created through reverse engineering, served as the basis for the analysis. The models of both traditional (T-S) and bioinspired (B-S) subsoiler tines for comparative assessment were developed. The EDEM simulation model’s performance was calibrated using soil penetration tests and integrated with multibody dynamics (MBD) to analyze the sandfish’s variable locomotion in sandy soil. The impact of linear and sinusoidal locomotion at velocities of 0.8 m/s, 1.0 m/s, and 1.2 m/s on resistance and soil disturbance were investigated and contrasted. The congruence between measured and simulated resistance-depth curves for T-S and B-S models was desirable, with maximum resistance errors of 2.54% and 2.47%, respectively, confirming the simulation model’s accuracy in predicting mechanical interactions. A comparison of characteristic angles validated the close correlation between simulated and actual sandfish locomotion in soil. Stress analysis during soil locomotion of the sandfish head indicated a 25.1% reduction in resistance with sinusoidal motion compared to linear motion. At the specified velocities, sinusoidal locomotion of the subsoiler tine showed resistance reductions of 6.75%, 7.39%, and 9.40%, respectively, relative to linear locomotion. The mechanism of resistance reduction in sinusoidal locomotion was further verified through soil compression force analysis, supporting the adoption of sandfish-inspired sinusoidal behavior as an innovative approach to enhance efficiency in agricultural practices. Keywords: Bioinspired design, DEM-MBD simulation, Sandfish (Scincus scincus), Sinusoidal locomotion, Subsoiling.

Using soft soil models in geotechnical engineering: a review paper

Soil is considered a complicated material as, in general, the behavior under loading is non-linear in addition it is anisotropic material and its behavior is time-dependent. Various models were developed in the method of finite element for modeling the behavior of soil under different loading cases, and it must be known that no constitutive model is available that can simulate completely the actual soil behavior under all conditions. This paper attempts to investigate the soft soil model and present a discussion about the advantages and disadvantages for the purpose of giving an overview, and discussing the main finding of the previous studies regarding using the Soft Soil model in the numerical analysis of geotechnical engineering problems and applications. In this research, it was observed from the previous studies that the relation between the modified compression index (λ*) and unloading index (κ*) is from (5 to 10). The Soft Soil model gives a stiffer stress-strain behavior compared to Hardening model. Using this model for compressible soils needs a longer calculation time than other models as the material stiffness matrix was included in each calculation step. It shows satisfactory results in the analysis of the settlement of immediate and consolidation cases of foundation in clayey soil than the model of Mohr-Coulomb.

Settlement prediction of shallow foundations for quality controls of sandy hydraulic fills

This paper describes a procedure for settlement prediction of shallow foundations on carbonate sands, but it is fully applicable and valid for siliceous sands. For practical purposes, the design of shallow foundations resting on medium dense and dense granular soils is typically governed by limiting settlement to tolerable values. Predicting foundation settlement is therefore important, but in standard practice it is necessarily based on indirect (and therefore often conservative) determinations of soil compressibility (or modulus), due to the intrinsic difficulties in obtaining direct measurements.While numerical analyses incorporating non-linear soil behaviour may be a preferred method for computing expected total and differential settlement of shallow foundations of given geometry and stiffness on sand under static loading, the method described in this paper consists of a simplified and expeditious method based on equivalent linear elasticity. The method uses: i) the elastic soil stiffness profile at small strain, E0(z) obtained from the shear wave velocity as the primary measurement of deformability and ii) the reduction in modulus as a function of strain magnitude, E(ε) to account for stiffness non-linearity. The beneficial effect on the soil initial stiffness of the applied footing load is also considered. The method was developed as an on-site tool for checking the compaction of hydraulic fills made of carbonate sand to form artificial islands, but its application can be extended to other natural and anthropogenic coarse-grained materials.

The Sustainability of Using DuraCrete as Cement Additive to Estuarine Soft Soil Stabilization

Large areas of estuarine deposits exist on the coastal plains of the southeast Queensland coast with a countered depth of up to 30 m. These deposits are categorized as sediments that originated during the Holocene Age. The sediments have not been consolidated or subjected to considerable pressure since the end of the Ice Age. The structure of these deposits consists of large ratios of porosity, causing high soil compressibility, which lowers the bearing capacity of the soils. Therefore, the soils of the region cannot maintain sufficient support for construction loads, and consequent malfunctions could occur in short-term and long-term periods. The objective of this paper is to investigate the suitability of new soil stabilization additives in the southeast Queensland region and the optimum additive content of cementitious materials and an advanced mixing modifier branded as DuraCrete. A combination of Portland cement and DuraCrete was used as a soil additive. Three DuraCrete-to-cement ratios were used: 2%, 3%, and 4% by weight. Soil collected from the Port of Brisbane region was treated by adding the additives as a percentage of its weight; four percentages were considered: 10%, 20%, 25%, and 30% for each combination of additives. The performance of the treated soils was examined under unconfined compression after 28 days of curing. The results revealed that increases in the unconfined compressive strength were detected as DuraCrete was added to the mixtures. For 30% additives, increases of about 15%, 34%, and 17% were detected when DuraCrete was added as 2%, 3%, and 4%, respectively. The results also revealed that 3% DuraCrete content provided significant stabilization compared to 2% and 4% for 25% and 30% additive-treated soils; such behavior was also observed for the specimens of 25% content of additives. Additionally, DuraCrete can be considered a promising material that can be combined with cement to obtain the desired stabilization of soft soils.

The influence of the parameters of engineering protective structures on the effectiveness of their use in densely built-up territory

A study of the influence of application of an engineering protective screen made of small-diameter driven piles on the existing building deformations, caused by the arrangement of the pit fence made of bored piles, was carried out. The study was carried out with the help of numerical modeling using the method of finite elements, which allowed to display the work of the system "soil base - engineering protective structures - the foundation of the existing building" with different parameters of the protective screen. The influence of the following parameters is shown:
 1) the depth of laying the protective screen L in relation to the depth of the compressible soil zone (Hst).
 2) the position of the protective screen between the retaining structures of the pit and the existing building.
 3) rigidity of the screen – the ratio of the step to the diameter of the piles of the engineering protective screen.
 4) the distance between the existing building and the pit in relation to the depth of the enclosing structures of the pit of the new construction.
 The tasks were modeled in a spatial arrangement with the task of the system "soil base - enclosing constructions of the pit - protective screen - foundations of the existing building". The soil environment was modeled using the Hardening Soil Model. The calculation was carried out in stages.
 The variation of the parameters of the protective screen was carried out for the historical building, which in most cases was made according to a rigid wall construction scheme with strip foundations.
 The foundation depth is 1.2 - 3.0 m and the foundation width is 1-2 m. The average pressure under the foundation is 150-250 kPa.
 The rational depth of the foundation and the position of the protective screen between the existing building and the pit of the new construction were established.
 The area of effective application of the protective screen was revealed, depending on the distance between the building and the pit fence.
 The effective stiffness is established depending on the change in the relative distance between the poles of the protective screen.

Geotechnical Behaviour of Gypseous Soil Treated by Geopolymer Additives

Gypseous soil is well-known for its numerous engineering problems. When this soil is exposed to water, the gypsum in the soil dissolves, causing the buildings built on it to collapse; so, treating gypseous soil is important for improving its engineering characteristics. The present paper focuses on studying the effect of adding geopolymer on mechanical characteristics of gypseous soil. This study presents the results obtained from a series of experimental tests, including direct shear, consolidation, and collapsibility tests. Tests were conducted on samples of gypseous soil taken from depth 1.5 meters below ground level with gypsum content of 41%. The geopolymer was used in three different molarities for the collapse test (10M, 12M, and 14M) and a 14 molarity only for the shear and consolidation tests, where equal proportions of fly ash were combined with an alkaline activator that was composed of sodium hydroxide and sodium silicate. The binder (fly ash + alkaline) to the soil was added to the treated samples during mixing at a rate of 20% by weight. The findings showed that treating the soil with geopolymer leads to a notable enhancement in the angle of internal friction of the soil particles from (37 to 42) degrees. as well as a reduction in the soil compressibility and a reduction in the susceptibility of the soil to collapse, with an improvement degree of 64% when using a geopolymer with a molarity of 14 M. This improvement was achieved by using a geopolymer with a higher concentration of NaOH. The best results were achieved when a geopolymer with a molarity of 14 was used, which is the ideal ratio.

LAND SUBSIDENCE IN WUHAN REVEALED USING A MULTI-SENSOR INSAR TIME SERIES FUSION APPROACH

Abstract. Satellite Interferometric Synthetic Aperture Radar (InSAR) is widely utilized for topographic, geological, and natural resource investigations. However, many existing InSAR studies on ground deformation are limited to relatively short observation periods and single sensors. This paper introduces a novel method for fusing multi-sensor InSAR time series data, specifically designed to address scenarios involving partial overlaps and temporal gaps. The method employs a new Power Exponential Knothe Model (PEKM) to fit and fuse overlaps in the deformation curves, while a Long Short-Term Memory (LSTM) neural network predicts and fuses data during temporal gaps in the series. In this study, the city of Wuhan in China was selected as the experimental area. SAR datasets from COSMO-SkyMed (2011–2015), TerraSAR-X (2015–2019), and Sentinel-1 (2019–2021) were fused to map long-term surface deformation over the past decade. An independent InSAR time series analysis from 2011 to 2020, based on 230 COSMO-SkyMed scenes, was used as a reference for comparison. The correlation coefficient between the fusion algorithm’s results and the reference data is 0.87 in the time overlapping region and 0.97 in the time-interval dataset. The overall correlation coefficient of 0.78 demonstrates that the proposed algorithm achieves a similar trend as the reference deformation curve. Based on the long time series settlement results obtained through fusion, a detailed analysis of the causes of settlement was conducted for several subsidence zones. The subsidence in the Houhu area is primarily attributed to the consolidation and compression of soft soil. Soil mechanics were employed to estimate the expected completion time of subsidence and calculate the degree of consolidation for each year. The COSMO-SkyMed PSInSAR results indicate that the area has entered the late stage of consolidation and compression, gradually stabilizing over time. Furthermore, the subsidence curve observed in the area around Xinrong reveals that the construction of an underground section of subway Line 21 has caused significant settlement in that particular region. The high temporal granularity of the PSInSAR time series also enables precise detection of a rebound phase following a major flooding event in 2016. The experimental results demonstrate the accuracy of the proposed fusion method in providing robust time series for analyzing long-term land subsidence mechanisms. Additionally, these findings unveil previously unknown characteristics of land subsidence in Wuhan, thus clarifying the relationship with urban causative factors.

Changes of water in different states during peat soil compression

Changes of water in different states during peat soil compression

Sensitivity of granular pile dimension parameters to deformation response of soft ground under building load

Granular pile is one of the proven soil improvement mechanisms applied especially for reinforcement of compressible soils supporting light structures. The improvement performance of granular piles is influenced by various factors including the dimension parameters (length, spacing and diameter of the piles). The influence of these three dimension parameters on deformation response of reinforced weak soil has widely been reported. However, the most influential parameter affecting deformation of the weak soil has not been clearly identified. Apparently, these dimension parameters do not equally influence the performance of stone columns in lessening soil deformation. Hence, comparative analysis was carried out in the current study to find out the dimension parameter to which deformation of stone column reinforced weak ground is most sensitive. Finite element based parametric numerical analysis was conducted to simulate the weak ground reinforced with a group of granular piles supporting light weight building. For the parametric study, five dimensions for each parameter (diameter, spacing and length) were considered. The dimensions were purposely varied by uniform percentage increase. Field settlement monitoring data was used to track deformation response of the site and validate the finite element results. The numerical analysis reveals that the simulation results have good agreement with the field settlement monitoring data. From sensitivity view point, column spacing was found to be the most controlling and influential parameter affecting deformation of the reinforced weak soil. Similarly, column length is the dimension parameter to which ground deformation is least sensitive.

Durability of clayey soil stabilized with calcium sulfoaluminate cement and polypropylene fiber under extreme environment

Calcium Sulfo-Aluminate Cement (CSAC) is gaining interest among researchers, consultants, engineers, and environmentalists as a prospective replacement of Ordinary Portland Cement (OPC) across many construction industries. The main reason is that the production of CSAC generates a lower carbon footprint as compared to OPC cement production. Other benefits of CSAC include quick bonding & strength development, and less shrinkage. Many studies are available and ongoing on the advantages and limitations of CSAC in concrete. However, only a few studies are available on its application in soil stabilization. Therefore, the efficiency of CSAC for soil stabilization is a topic of discussion in geotechnical engineering. In this research, a locally sourced highly compressible clayey soil was stabilized with different combinations of CSAC and polypropylene fiber (e.g., 5.0%, 7.5% & 10.0% of CSAC and 0.5% & 1.0% polypropylene fiber), and its effectiveness was observed and evaluated in terms of durability (Wetting-Drying and Freezing-Thawing tests) against extreme environments and also checked Unconfined Compressive Strength (UCS) as per American Society of Testing and Materials (ASTM) guidelines. The findings of this research are evaluated in terms of percentage of soil loss, change in moisture content and volume, and loss of strength after durability exposure. Moisture content and bulk unit weight were determined after each stage in the Freezing-Thawing durability cycles. Samples prepared with 10.0% of CSAC and 1.0% of fiber were able to survive all durability cycles of Wetting-Drying with PCA (Portland Cement Association) soil-loss percentage criteria. On the other hand, samples prepared with 10.0% cement with 0.5% as well as 1.0% fiber were able to survive all durability cycles of Freezing-Thawing with PCA soil-loss percentage criteria. These survived samples showed a significant amount of unconfined compressive strength even after being subjected to these durability cycles.

Effects of biochar on the compressibility of soil with high water content

This study investigates the potential utilization of biochar in reclamation fills to improve the compressibility of soil with high water content. Biochar, a recycled carbon-rich biomass commonly used for contaminated soil remediation and carbon sequestration, is examined for its impact on the compression behavior of treated soils. The influence of biochar content, initial water content (w0), and biochar saturation on the compression behavior of biochar-treated soils with high water content is analyzed. The results revealed that the addition of both raw biochar and biochar saturated with water significantly enhances the remolded yield stress (σ′yr) and reduced the void ratio (eyr) at σ′yr. Raw biochar exhibits higher σ′yr and lower eyr values compared to water-saturated biochar, mainly due to its greater water absorbing potential of raw biochar. The variations of σ′yr and eyr induced by biochar can be attributed to the decrease in initial void ratio (e0) and the increase in void ratio at liquid limit (eL), which can be effectively normalized using empirical equation developed for reconstituted soil without biochar. Furthermore, the compression parameters (e*100 and C*c) show a decreasing trend with increasing biochar content and decreasing initial water content. Soil with saturated biochar displays higher e*100 and C*c values in comparison with soil with raw biochar. The changes in e*100 and C*c corresponded well to empirical equations developed for reconstituted soil without biochar, indicating that the compressibility changes induced by biochar depended on variations in physical properties (e0 and eL), following similar patterns observed in reconstituted soils without biochar. Therefore, the compression curve of biochar-treated soil in the postyield regime can be effectively normalized by using void index into the ICL or EICL, suggesting its practical applicability for predicting the compressibility of reclamation soil with biochar. These findings demonstrate that biochar-treated soil with high water content exhibits favorable geotechnical properties, making it suitable for use as soil reclamation fills or in landfill applications.

Characterization of black cotton soil by using granulated blast furnace slags

Soil stabilization is the best way to enhance the characteristics of low-quality soil. The properties may include, permeability, compressibility, strength, durability, etc. It is required when there is a need for construction on the poor sub-soils that are not suitable for that particular construction. Black cotton soil (BC) has a high clay content and is also considered as compressible soil with shrinkage and swelling characteristics and a constrained bearing capacity. It expands during the rainy season due to water absorption and contracts during the summer, which gives rise to serious structural deterioration. This study targets to stabilize this black cotton soil using ground granulated blast furnace slags (GGBS). It is a by-product of iron found in the blast furnace. It is extremely cementitious and contains a large amount of calcium silicate hydrates that increase its durability, strength, and appearance. In this study, GGBS is used at different percentages such as 5 %, 10 %, 15 %, 20 % and 25 %. Sodium hydroxide is also added in various dosages from 0.5 M, 1 M, 2 M, 4 M and 6 M. The major goal of this study is to investigate how GGBS affects the engineering parameters such as Atterberg’s limit, differential free swell (DFS), Compaction characteristics (i.e., maximum dry density (MDD) and optimum moisture content (OMC)) and unconfined compressive strength (UCS). The durability characteristics of soil-GGBS mixtures are also studied. Results show that as compared to virgin soil, adding 25 % of GGBS to BC soil resulted in an increase in MDD of around 16.5 % and a decrease in OMC of about 29 %. Further, it is also found that compared to (Soil + 20 % GGBS), the UCS value of the (Soil + 20 % GGBS + 4 M NaOH) mixture increased by roughly 36.5 %. Finally, the optimum concentration of GGBS content is found as 20 % while treated with 4 M NaOH solution.

Numerical Simulation of Artificial Recharge Groundwater Effect on Overlying Soft Clay Compression Control

Soil deformation is prone to occur in the process of the foundation pit dewatering. A large number of metro existing tunnels are located in soft soil layers. The compression of soft soil poses a threat to metro existing tunnels. Previously, plenty of research on foundation pit dewatering is focused on the hydraulic head and deformation characteristics of the aquifer. However, the law of water releasing and compression deformation of overlying soft soil has not been taken seriously. In order to study the artificial recharge groundwater effect on overlying soft clay, a three-dimensional seepage–soil deformation coupling numerical model was established. The theoretical basis of the model is Darcy’s law and the principle of effective stress. A foundation pit located in Nanjing, China was selected as an example. The numerical model was used to simulate the hydraulic head and soil deformation caused by foundation pit dewatering and artificial recharge groundwater outside. The result shows that, due to the difference of hydraulic head between the aquifer and the aquitard reducing, it also has a good control effect on the deformation of the soft soil by recharging water into the aquifer. The location of recharge wells around the metro existing tunnel can control the soil deformation effectively, which could help to reduce the impact on the metro existing tunnel.

Effect of Lead on Strength Behaviour for Spiked Contaminated Soil

Deterioration of geo-environmental quality caused by the heavy metal in contaminated soil leads to changes in physical, mechanical, and chemical properties of soil. It is important to study the effect of contamination of the geotechnical properties of soil. The main aim of this research is to study the impact of lead and incubation time on polluted soil compressibility. The soil samples were got from Kaolin Malaysia Sdn Bhd in Tapah Perak. The soil samples were spiked with two concentrations of lead nitrate (1000 mg/kg and 2000 mg/kg), and were incubated for 7, 14, 21, and 28 days. The contaminated samples were created using a mixture of distilled water and lead nitrate. The physical, mechanical, and chemical properties of control and contaminated samples were assessed to analyse the effect of lead nitrate on these properties. Lead nitrate causes the increasing of plastic limit and liquid limit, reduction of maximum dry density and optimum moisture content. In addition, the unconfined compressive strength was decreased by 4.2% for 1000mg/kg while 24.3% with 200 mg/kg. This is with increasing concentration of lead nitrate as well as incubation period. Collapsibility increases with increased concentration of lead nitrate and time of incubation due to increased compressibility capacity. The important thing about this study is to provide a database for the future development of the site area contaminated with heavy metals such as landfill, landfill, agriculture and industry.

Mechanical Properties and Microscopic Mechanism of Basic Oxygen Furnace (BOF) Slag-Treated Clay Subgrades

Civil engineering faces a substantial challenge when dealing with soft and compressible clayey soils. Conventional soil stabilization techniques involving ordinary Portland cement (OPC) result in notable CO2 emissions. This study explores the utilization of basic oxygen furnace (BOF) slag, a by-product of steel production, for strengthening kaolin clay. This research investigates the influence of BOF slag particle size, BOF slag content, and the use of activators such as lime and ground granulated blast-furnace slag (GGBFS) on the stabilization of kaolin clay. The strength development is assessed through unconfined compressive strength (UCS) test, bender element (BE) test, and scanning electron microscopy (SEM). The findings reveal that higher BOF content and extended curing periods enhance soil strength, and lime and GGBFS effectively augment the stabilizing properties of BOF slag. Stabilizing kaolin clay with a 30% BOF/GGBFS mixture in a 50/50 ratio with 1% lime and curing for 7 days yielded a compressive strength of 753 kPa, meeting the Federal Highway Administration’s requirement for lime-treated soil. These combined measures contribute to developing a more robust and stable material with enhanced geotechnical properties.

Basin boundary seismic effects in Mexico City southern region

AbstractRapid changes in geotechnical and geological ground conditions lead to significant ground motion variability. This condition mainly occurs at the so-called basin edges, where there is an abrupt transition between soft highly compressible soils and stiffer materials. This problem becomes more relevant in areas where ground subsidence drastically changes the dynamic response of high plasticity clay deposits, such as those found in Mexico City, due to fundamental site period evolution with time. This paper presents site response analyses at an abrupt transition area in the southeast Mexico City region, along the edges of the Xochimilco-Chalco lakes. Considerable damage associated with three-dimensional wave propagation effects was observed in this zone during the September 2017 Puebla-Mexico earthquake. A series of three-dimensional finite difference numerical models of the basin edge were developed to evaluate ground motion variability, considering topographic effects and soil non-linearities. Good agreement between the computed response and the observed damage during the 2017 Puebla-Mexico earthquake reconnaissance was found. In addition, several normal and subduction events with a return period of 250 years were considered to evaluate the effect that frequency content, and strong ground motion duration have on the soil response variability. From the results gathered here, it was established the relevance of accounting for three-dimensional wave propagation fields to assess site effects at basin-edge zones properly and to be able to implement proper risk mitigation measurements at these zones.

The Development of a Draft Force Prediction Model for Agricultural Tractors Based on the Discrete Element Method in Loam and Clay Loam

In the field of agricultural machinery, various empirical field tests are conducted to measure design loads for the optimal design and implementation of tractors. However, conducting field tests is costly and time-consuming, with many constraints on weather and field soil conditions, and research utilizing simulations has been proposed as an alternative to overcome these shortcomings. The objective of this study is to develop a DEM-based draft force prediction model that reflects differences in soil properties. For this, soil property measurements were conducted in two fields (Field A in Daejeon, Republic of Korea, and Field B in Chuncheon, Republic of Korea). The measured properties were used as parameters for DEM-based particle modeling. For the interparticle contact model, the EEPA contact model was used to reflect the compressibility and stickiness of cohesive soils. To generate an environment similar to real soil, particle mass and surface energy were calibrated based on bulk density and shear torque. The soil property measurements showed that Field B had a higher shear strength and lower cone index and moisture content compared to Field A. The actual measured draft force was 19.47% higher in Field B than in Field A. In this study, this demonstrates the uncertainty in predicting draft force by correlating only one soil property and suggests the need for a comprehensive consideration of soil properties. The simulation results of the tillage operation demonstrated the accuracy of the predicted shedding force compared to the actual field experiment and the existing theoretical calculation method (ASABE D497.4). Compared to the measured draft force in the actual field test, the predictions were 86.75% accurate in Field A and 74.51% accurate in Field B, which is 84% more accurate in Field A and 37.32% more accurate in Field B than the theoretical calculation method. This result shows that load prediction should reflect the soil properties of the working environment, and is expected to be used as an indicator of soil–tool interaction for digital twin modeling processes in the research field of bio-industrial machinery.

Track-bridge deformation relation and interaction of long-span railway suspension bridges subject to strike-slip faulting

During earthquakes, the long-span railway bridges crossing active faults are more vulnerable because of the combined effects of pulsed ground motions and surface dislocations. To study the track-bridge deformation and interaction of long-span railway suspension bridges crossing the strike-slip faults, the refined finite element model of a ballasted track-bridge-pile-soil coupled system was established using the nonlinear finite element software ANSYS/LS-DYNA. A detailed and systematic numerical simulation was conducted from the soil cracking and compression during the ground surface rupture, pile–soil interaction, and three-dimensional track constraints to track-bridge deformation relationships and interactions. One-dimensional wave propagation theory was employed to derive the ground motions on the bedrock according to ground surface-measured seismic records. The influences of the fault-crossing angle (FCA) and permanent ground rupture displacement (PGRD) on the seismic responses and track-bridge interaction were analysed by considering the pile–soil interaction and site response effect. A method for calculating the track curvature radius based on track deformation is presented to evaluate the running traffic conditions of the trains. Additionally, the stability of the ballast bed was estimated using the track-bridge relative displacement. The conclusions drawn can be applied in practical seismic design and train running safety assessment of long-span railway suspension bridges crossing the strike-slip faults.

Predicting clay compressibility for foundation design with high reliability and safety: A geotechnical engineering perspective using artificial neural network and five metaheuristic algorithms

This study aims at predicting clay compressibility (clay compressibility) for foundation design with unprecedented reliability and safety. To achieve this goal, we set forth several scientific objectives to enhance the accuracy of clay compressibility predictions and ensure the robustness of our models. Firstly, we explored an updated dataset comprising diverse clay types, focusing on the intricate relationship between clay compressibility and essential soil properties. By incorporating particle size distribution, the ratio between liquid limit (wLL) and plasticity index (PI), and the ratio between void ratio (eLL) and wLL, our objective was to gain a comprehensive understanding of clay behavior, facilitating more accurate predictions. Secondly, we employed Artificial Neural Networks (ANNs) as our primary modeling tool. ANNs, with their capacity to discern complex patterns within data, formed the foundation of our predictive model. Our scientific objective was to harness the power of ANNs to capture subtle relationships among input variables, thereby ensuring a robust foundation for clay compressibility predictions. To further refine our predictions, our third objective was to optimize the ANN model. We utilized five distinct metaheuristic algorithms—Bird Swarm Algorithm (BSA), Dragonfly Optimization (DO), Elephant Herding Optimization (EHO), Jaya Algorithm (JA), and Whale Optimization Algorithm (WOA). Our aim was to fine-tune the ANN model's parameters using these algorithms, capitalizing on their strengths to achieve superior predictive performance. Additionally, our study aimed to pioneer the development and evaluation of hybrid models for forecasting clay compressibility. By integrating the ANN model with the metaheuristic algorithms (BSA-ANN, DO-ANN, EHO-ANN, JA-ANN, and WOA-ANN), our objective was to create hybrid frameworks that synergistically combined the strengths of both approaches. We rigorously evaluated these hybrid models, ensuring their efficacy and reliability in practical engineering applications. Crucially, we validated our models through practical engineering scenarios. For this purpose, we prepared 30 new soil samples mirroring real-world conditions. Our objective was to apply the developed models to these samples, affirming their effectiveness and reliability in actual foundation design applications. In pursuit of identifying the most accurate and reliable predictive model, our final objective focused on the BSA-ANN model. Remarkably, this model demonstrated an exceptional accuracy of 99.8%. Our objective was to establish the BSA-ANN model as the preferred choice for practical engineering applications, ensuring high reliability and safety in foundation design.