bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on the density of underwater sand and gravel fillings based on geotechnical centrifugal tests
Authors: Li Bo , Wei Songtao , Shen Liqun , Chen Lei 
Published: May 2024

Abstract
The density of underwater dumping materials plays a major role in cofferdam engineering designs. However, it is difficult to accurately measure the density of underwater dumping materials. This study investigated the influence of particle size distribution of granular materials on the density of underwater filling materials. Considering the underwater dumping project of a hydropower station dam in the Han River as the prototype condition, several underwater dumping density centrifugal tests were conducted on sand gravel and sand mixtures. Based on the CKY200 large-scale geotechnical centrifuge, a single-embankment vertical-blockage underwater filling test device in a centrifuge field was developed. The results demonstrated the relationship between the compactness of the dumping body and the grading of loose particles, depth of dumping, and height of the upper loading. This indicates that the underwater filling material has a higher compactness and can reach a dense state. When the grading is poor, the compactness decreases. The greater the depth of filling, the greater the compactness. When vertical compression was applied to the upper part of the backfill, the compactness of the backfill, particularly in shallow areas, was significantly improved. These results provide insights for the design and construction of underwater dumping water conservation systems.
Numerical study of borehole instability of large diameter monopile during the window period between drilling and pile driving
Authors: Zhang Q , Chai Y H , Zhu W X , Ye G L 
Published: May 2024

Abstract
Large-diameter monopiles are among the most widely used offshore wind turbine foundations. Implementing drive-drill-drive construction techniques in a decomposed granite seabed may lead to borehole instability during the window period between drilling and pile driving. In this study, the borehole stability of a large-diameter monopile in a weathered granite seabed was investigated using the discrete element method. A linear parallel bond model was employed to simulate the bonding effect among weathered granite particles, and the influence of pore water was considered. The results indicated that soil shear failure caused by excavation unloading was the primary cause of borehole instability. The exposed height of the unsupported borehole significantly influenced the occurrence of borehole instability. The greater the exposed height of the unsupported borehole, the larger the soil arch required to maintain the stability of the borehole, and the less stable the soil arch becomes. Moreover, the susceptibility to borehole instability and collapse also increased.
In situ monitoring of the impacts of Melaleuca styphelioides transpiration on soil water dynamics in an urban environment
Authors: Sun Xi , Li Jie , Ren Gang 
Published: May 2024

Abstract
Expansive soils are susceptible to substantial cyclical moisture variations under the prevailing climate, experiencing considerable shrinkage during drought and swelling when water availability increases. These dynamic volumetric changes jeopardize the functionality of lightweight infrastructures with shallow foundations. The presence of trees may amplify seasonal soil movements, as extensive water uptake by root networks in the summer months can induce soil moisture depletion and the resulting desiccation-driven settlement around the trees. This study assessed the drying effect of mature Melaleuca styphelioides on soil movement and water dynamics at an urban experimental site in Melbourne, Australia, instrumented for in situ monitoring over 12 months. Sap flow instrumentation was used to quantify seasonal variations in tree transpiration. The monitoring results revealed that the drying influence of the tree has extended to a depth of 2.2 m. Tree root-induced soil desiccation occurred 4.0 m away from the tree, as evidenced by the seasonal soil movement profiles. Linear regression analysis showed that the soil water content explained 60% of the variability in tree transpiration. In contrast, the soil water content and suction exhibited a robust negative correlation (R2=0.96) within the active root zone.
Simple method to determine coefficient of permeability of unsaturated soil
Authors: Nguyen T B , Zhu Y L 
Published: May 2024

Abstract
This study introduces a novel transient method for determining the unsaturated coefficient of soil permeability, requiring the measurement of volumetric water content and corresponding pore-water pressures at three distinct points. This distinctive advantage of the method lies in eliminating the need to measure or control the flux at any point within the soil profile. The proposed method was validated through numerical simulations that performed one-dimensional seepage analysis, followed by a comparison of the calculated unsaturated coefficients of permeability with the input data. The strong agreement between the compared results validates the feasibility of the proposed method for determining the unsaturated coefficient of soil permeability. Moreover, a spatial interval of less than 5 cm is recommended to ensure accurate results for the unsaturated coefficient of permeability when employing this method.
Physical model test on rainfall-induced instability of silty slope
Authors: Bai M H , Gao X G , Wang J P 
Published: May 2024

Abstract
In the context of ecological conservation and high-quality development in the Yellow River Basin, extensive silty slopes have emerged in the downstream alluvial plain regions owing to engineering construction. These slopes are susceptible to rainfall infiltration-induced instability, resulting in geological hazards, such as landslides and mudslides. This study explored the hydrodynamic characteristics and spatiotemporal evolution patterns of silty slopes under rainfall conditions, focusing on the alluvial silty slopes of the Yellow River. Experiments were performed to monitor variations in soil water content, soil water potential, and pore water pressure at various locations on the slope. Slope instability and failure under rainfall were monitored using high-frequency photography technology. The results indicated the development of layered vertical collapses along the surface of the slope, starting from the base and accumulating below the failure point. With increasing rainfall intensity, soil water content, soil water potential, and pore water pressure increased earlier at various points on the slope. These findings provide crucial experimental data and a theoretical foundation for exploring the instability mechanisms within silty slopes in the lower Yellow River’s alluvial and siltation plain areas during rainfall events. Moreover, they are significant for formulating more effective strategies for geological disaster warning and prevention.
Macro-meso properties and damage constitutive model of sandstone under chemical and freeze-thaw environments
Authors: Liang Y , Huo R , Song S , Zhang Y , Wang B , Jie J 
Published: May 2024

Abstract
The coupled effect of chemical corrosion and freeze-thaw cycle degrades the physical and mechanical properties of rock, affecting the safety and durability of underground rock mass engineering. This study investigated the deterioration laws of sandstone under pH = 1 and 3 chemical and freeze-thaw cycle action for different time considering macro and meso scales. The stress-strain curve of sandstone under uniaxial compression can be divided into compaction, elastic deformation, yield, and post-peak stages. The compaction of sandstone after chemical and freeze-thaw cycle action became apparent, elastic stage was relatively shortened, elastic modulus and peak strength decreased, and peak strain increased. The density and homogeneity of sandstone declined as per the CT scan and image processing technologies. The deterioration was prominent with longer action time and smaller pH value of the solution. After 120 days of pH = 1 and 3 chemical and freeze-thaw cycle action, the peak stress of samples decreased by 22.10% and 15.16%, the elastic modulus declined by 89.57% and 85.09%, the peak strain increased by 96% and 62%, and the damage variables reached 3.27% and 1.83%. The damage constitutive model of sandstone was established using statistical damage theories. The theoretical stress-strain curves were consistent with experimental ones. The insights of this research have implications for the theoretical foundation of safety assessments and disaster prevention in practical engineering scenarios under chemical and freeze-thaw environments.
A discrete approach for modelling the permeability evolution of granite under triaxial and true-triaxial stress conditions
Authors: He Chen , Yao Chi , Shao Yulong , Jiang Qinghui , Zhou Chuangbing 
Published: May 2024

Abstract
In deep underground engineering, modelling the seepage characteristics of rock masses under complex stress conditions is crucial for the safe construction and stable operation of a project. The permeability of the rock mass is not only controlled by its internal pore structure but is also closely related to the deformation and fracturing of the rock. Although discrete methods offer advantages in describing the formation and development of fractures, these methods still face challenges due to the difficulties in establishing microscopic seepage models. This paper introduces a new hydro-mechanical coupled numerical model. In this model, a simple method is proposed to couple the Rigid-Body-Spring Method (RBSM) for rock deformation and fracturing simulation and the Equivalent Matrix-Fracture Network (EMFN) for seepage simulation. Subsequently, the model is employed to simulate the permeability of granite under three-dimensional stress conditions. The simulation results show that under hydrostatic stress conditions, the model accurately captures the decrease in permeability due to pore compression and collapse. Additionally, under deviatoric stress conditions, it reveals the stage-wise increase in permeability caused by granite fracturing. Finally, the model is applied to study the permeability evolution behaviour of rocks under true triaxial stress conditions. The results unveiled the significant impact of the intermediate principal stress on permeability evolution and revealing the microscopic mechanisms underpinning these effects. This paper paves a way for enhancing the application of discrete methods in forecasting the permeability evolution behaviour of intricate rock masses.
Method for identifying the position of crack tip by displacement distribution based on digital image correlation
Authors: Zhao Cheng , Fu Jiao , Xing Jinquan , Xiang Fubin , Qian Yuan 
Published: May 2024

Abstract
Determining the position of crack tip is crucial for rock fracture characteristic analysis. This study aims to establish a quantitative standard for determining crack tip positions in crystalline rocks based on digital image correlation (DIC). Semi-circular bending (SCB) tests were conducted on four types of rocks under three-point bending. Optical microscopy and DIC were used to investigate characteristics of the horizontal displacement fields around the crack tips. A significant disparity in the displacement gradient was observed across the crack tips, with the internal gradient being approximately 3–5.1 times higher than the external gradient. A critical value ranging from 0.41%–0.64% was determined for the high internal displacement gradient (∂u/∂x) at a 20 pixel resolution equivalent to 1 mm. Furthermore, a novel DIC-based method was proposed that used three patterns of opening displacement gradients to classify SCB specimens into non-cohesive, cohesive, and elastic zones, providing a quantitative determination of Type I crack tip positions. This study offers valuable insights and a crack tip determination method based on DIC gradients, applicable for assessing parameters such as the crack extension length and fracture process zone length.
Meso-mechanical behavior of crystalline rocks: An image-based discrete element method
Authors: Pan Haoyu , Zhao Cheng , Chen Huiguan , Yang Hongwei , Xing Jinquan 
Published: May 2024

Abstract
This research examines the meso-mechanical behavior of rock materials under various loading conditions, with a focus on the influence of mesoscale heterogeneity in crystalline rock specimens. Traditional approaches often rely on a limited set of statistical parameters for constructing numerical models, failing to capture the complex mesoscale heterogeneities integral to rock mechanics. To overcome this limitation, the study utilizes an advanced image-processing technique to accurately identify mineralogical features within rock microstructures. The extracted mineralogical data were then integrated into a discrete element method (DEM) model to explore the mesoscale mechanical responses of crystalline rocks. The results of the simulations indicated that mesoscale heterogeneities play a critical role in stress concentration localization, which in turn dictates the direction of fracture propagation and leads to a sophisticated interaction among various fracture pathways.
Sustainable development of pavement base stabilization using future road base material (FROBM)
Authors: Bualuang T , Jitsangiam P , Chusai N 
Published: May 2024

Abstract
Sustainable road construction has emerged as a critical issue in assessing natural resources and urban development. With the rapid expansion of pavement networks to meet growing traffic demands, road base construction relies heavily on the consumption of natural aggregates and Ordinary Portland Cement (OPC) through the cement-treated base (CTB) technique. This practice contributes to the global warming and greenhouse gas (GHG) emissions associated with road construction. This study investigated a novel road base material, Future Road Base Material (FROBM), which emphasizes both eco-friendliness and economic advantages. Fine crushed rock (FCR) served as the parent aggregate and was modified with a chemical binder comprising 4% of the FCR weight. The proposed sustainable cementitious material, functioning as a non-OPC binder, incorporated fly ash and hydrated limestone as pozzolanic materials, along with sodium hydroxide (NaOH) as an alkali additive. An asphalt emulsion (AE) was employed as a special additive to enhance crucial pavement engineering properties. Through life cycle analysis (LCA), the construction activities and material acquisition of each stabilized base technique were evaluated in terms of project costs and carbon footprints. The non-OPC binder offered sufficient compressive strength for a stabilized base course. Furthermore, the addition of AE improved the elastic modulus and modulus of rupture of the non-OPC binder-stabilized mixture. Utilizing a non-OPC binder and AE in the base layer provides advantages in terms of construction cost and environmental impact. Although the costs increased slightly, the GHG emissions were reduced by approximately 30% compared to conventional base materials, with equivalent functionality and service life for road construction. The proposed stabilizing agent reduced the operational processes and demand for natural aggregates compared with the unbound FCR base course. Road-base stabilization using a non-OPC binder and AE represents an innovative approach to mitigate waste in coal mining and power plant industries by transitioning to a cleaner product. The concept of the FROBM serves as a valuable guideline for the development of future sustainable pavement materials.
Simulation of soil-structure interaction of integral abutment bridges using advanced constitutive relations
Authors: Hassan M S K , Liyanapathirana D S , Fuentes W , Leo C J , Hu P 
Published: May 2024

Abstract
Integral bridges have been proposed as an attractive design concept that negate the requirements for expansion joints. However, owing to structural continuity, seasonal and diurnal thermal fluctuations have subjected the abutments to long-term cyclic interaction with approach backfills. This resulted in two notable geotechnical complications: ratcheting of lateral stresses and progressive soil deformation. To understand these phenomena, considerable research has been conducted using numerical methods. Here, either Winkler springs or simple constitutive relations, such as the Mohr-Coulomb model, are predominantly utilized. However, the former is based on monotonic displacement-dependent stiffness theories, and the latter is constrained by the limitations of the traditional yield surface plasticity. Hence, neither possesses the capability to simulate the hysteretic response, which is a characteristic of integral bridge approaches. Therefore, this study aims to present the advantages of using advanced constitutive relations to predict the long-term behavior of integral bridge approach backfills. First, using a lateral cyclic triaxial simulation, the significance of soil densification was highlighted by comparing the performance of the Mohr-Coulomb model with that of the bounding surface Dafalias-Manzari-2004 model. Subsequently, further comparisons were performed with the centrifuge model data of the integral abutment. At both the element and boundary value levels, the Mohr-Coulomb model could not capture the gradual accumulation of the lateral stresses. Conversely, the Dafalias-Manzari-2004 model can estimate the long-term passive pressure accumulation along the height of the abutment.
Pore structure characteristics of coral reef limestone: a combined polarizing microscope and CT scanning study
Authors: Xu J , Huang X , Zhang Z , Jin G 
Published: May 2024

AbstractCoral reef limestone is a special class of geological medium formed through long-term deposition following the death of reef-building coral groups. Because it retains the skeletal structure of marine organisms during its formation, its pore structure is hyper-developed and complex. Deciphering the pore structure of the coral reef limestone is important because it is closely related to its macroscopic physical and mechanical properties. This study conducted a comprehensive analysis of the pore structure features of two types of coral reef limestone collected from the construction site of a nuclear power station located in the South China Sea using a combination of polarizing microscopy and CT scanning technologies. The fractal dimension of the pore structure of the treated reef limestone image was calculated, and the pore structure characteristics were statistically analyzed by considering several parameters including porosity, pore size, pore equivalent radius, shape factor, etc. In addition, the directional feature of the pore structure was explored. The results show that the improved watershed segmentation algorithm can accurately segment the pore structure of reef limestone images; both coral reef limestone specimens are loose of high porosity; the fractal dimension of pore structure lay between 1.58∼1.75, indicative of a high self-similarity; the pore size of the two coral reef limestone specimens is quite different, and the distribution of equivalent pore radius conforms to the normal distribution law; the pore structure of the two samples had obvious directionality, which can be quantified using a directional tensor. This study sheds light on future investigations linking the microscopic structure and macroscopic properties of coral reef limestones.
Holding capacity of a novel hybrid helical-skirted foundation of offshore wind turbines
Authors: Norouzi Behnam , Wanga Yifa , Ye Guanlin , Li Zeliang , Tian Yinghui 
Published: May 2024

Abstract
A novel hybrid foundation consisting of a helical pile and a peripheral skirt was introduced in this study. This hybrid foundation exploits both the helical pile and the skirted foundation. This study focused on evaluating the undrained vertical holding capacity of this hybrid foundation in clay using three-dimensional finite element analysis. Their capacities and failure mechanisms were examined and compared. The analysis results showed that a significant increase in the vertical holding capacity was achieved compared to that of an individual component, which is attributed to the enhanced soil mobilization mechanism.
Study on the properties of nano-Fe3O4 modified asphalt materials based on molecular dynamics
Authors: Chen Xueqin , Zhang Yuhui , Liu Kailiang , Dong Qiao 
Published: May 2024

Abstract
Asphalt possesses the inherent ability to self-heal microcracks, with enhanced healing observed under active heating conditions. Nanomaterials have the capacity to alter the microstructure of asphalt blends, offering certain advantages in terms of asphalt performance. In this study, models of nano-Fe3O4 clusters and nano-Fe3O4/asphalt blending systems with varying particle sizes were established. Molecular dynamics simulations were employed to investigate the physical properties of nano-Fe3O4 and asphalt molecules at different temperatures, simulating the microwave heating process within a temperature range of 303 K to 373 K. The findings revealed that the diffusion coefficient of Fe3O4 clusters decreased with increasing particle size. Nonbonding interaction energy predominantly governed the binding between Fe3O4 clusters and asphalt molecules. The incorporation of nano-Fe3O4 was found to enhance the physical properties of asphalt. Peak values of the radius of gyration for asphaltene and aromatics indicated increased density, while asphaltene, colloids, and aromatics exhibited greater extensibility with the addition of nano-Fe3O4.
Dynamic characteristics and microstructure of clay reinforced by the splitting grouting method under subway dynamic loading
Authors: Zhou J , Zhou H , Tang Y 
Published: May 2024

Abstract
The splitting grouting reinforcement method is typically used to improve the stability of surrounding rock when constructing subways in water-rich and weak strata. However, in contrast to normal soil, the dynamic characteristics and microstructure of reinforced soil under cyclic loading of a subway necessitates further clarification to obtain a technical basis for controlling the deformation and settlement of the reinforced soil during later stages. Based on field-reinforced soft clay samples, this study analyzed the dynamic characteristics and microstructure of reinforced soft clay under cyclic loading through stress-controlled undrained cyclic triaxial and scanning electron microscope tests. The results showed that the lower the frequency or the larger the cyclic dynamic stress amplitude, the faster the residual strain development of the reinforced soft clay. There were three cyclic creep characteristic curves of reinforced soft clay: peak, base, and valley creep curves, and the development of base creep represented the overall trend of cyclic creep in reinforced soft clay. In addition, calcium silicate hydrate and ettringite were produced in the reinforced soft clay, which improved the connectivity between the soil particles.