bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simplified Model for Suction Pile Stiffness under Combined Loading in Elastic Soil: A Winkler-based Approach
Authors: Cui H , Shi Z , Huang M 
Published: May 2024

Abstract
Suction pile foundations are a promising option for offshore structures in deep locations covered by soft soil. A reasonable prediction of foundation stiffness may offer a reliable method for estimating the dynamic performance of the overall structure. Although the Winkler-based approach can effectively analyze the stiffness of caisson foundations, the current models can underestimate and/or overestimate the global stiffness subjected to combined loading under a relatively large embedment depth-to-diameter ratio L/D. Moreover, the non-linear distribution of local stiffness with depth has been neglected in current research methods. Thus, this study established a simplified Winkler model capable of providing reliable predictions of suction pile foundation stiffness under combined loading in homogeneous elastic soil. Finite element analysis (FEA) was performed to establish inter-relationship of local stiffness with soil properties and foundation geometries via the concept of “Inferred Winkler model.” Furthermore, the non-linear distribution of local stiffness with depth was considered. Finally, the proposed method was assessed against the FEA and current models to evaluate its applicability with different L/D subject to general single and combined loadings.
Constitutive modeling structural behaviors of Shanghai deep clay
Authors: Tu Zizhen , Qian Jiangu , Shi Zhenhao , Jiang Wenlan 
Published: May 2024

Abstract
The rapid development of underground engineering requires a comprehensive understanding of deep soils. Existing study about the deformation and strength behaviors of Shanghai clay is mostly focused on shallow soft clay (generally within 30 m depth), while counterpart for deep clay is needed. This work investigates the physical properties and mechanical behaviors of Shanghai deep clay (block samples of layer (8) obtained at a depth of around 50 m), via conducting a series laboratory tests including physical property tests, onedimensional consolidation tests and undrained triaxial compression tests, performing constitutive modelling. The results show: (1) Shanghai layer (8) clay can be classified as a low-plasticity silty clay, and the void ratio measured in the laboratory of the block samples is larger than remoulded samples; (2) The clay is a normally consolidated clay, and the block samples show greater compressibility and stronger initial structure; (3) The block samples show contraction behaviors in the undrained triaxial compression tests; (4) The structural behaviors is well captured by structural bounding surface model.
Asymmetric instability damage patterns of curved shield tunnels based on transparent soil visualization model tests
Authors: Zhang Xue , Zhang Mengxi , Fan Jie , Wu Huiming 
Published: May 2024

Abstract
With accelerated urbanization, underground structures have imposed significant restrictions on underground spaces. Urban shield tunnels must be designed using curved lines to avoid existing tunnels, pile foundations, and other structures. Over-excavation on the inner side of a curved tunnel during tunneling and the difference between the inner and outer jacking forces complicate research on excavation surface stability. In this study, a combination of transparent soil visualization model tests and numerical simulation methods was used to investigate the spatially asymmetric distribution patterns, focusing on the progressive destabilization damage of the soil and the soil arching effect in front of the excavation during construction of curved shield tunnels. Furthermore, the effect of the radius of curvature on the soil arch morphology in sandy soils was analyzed in detail. The results show that the soil displacement in front of the working face of the curved tunnel exhibited a crescent-shaped deflection toward the over-excavation side. The settlement tanks in the curved tunnel exhibited an asymmetric distribution along the center of the tunnel and were deflected to the over-excavation side. The smaller the radius of curvature, the greater was the deflection of the soil in front of the curved tunnel to the over-excavation side.
Investigation of engineering characteristics of red sand in Luanda, Angola
Authors: Xia Yuyun , Qiao Jianwei , Liu Zhenghong , Tang Lijun , Liu Min , Cheng Yongxiang , Jiang Wen , Huang Lei 
Published: May 2024

Abstract
Red sand is widely distributed on the west coast of Africa, south of the Sahara, and is an essential material for local engineering construction. Red sand possesses orthostasis and high sensitivity to water, exhibiting characteristics that are different from ordinary sandy soil. Laboratory and in-situ tests were conducted to assess its engineering characteristics, including collapsibility, shear characteristics, and bearing capacity. The water sensitivity of red sand was analyzed along with the images from a scanning electron microscope. The findings indicate that red sand can be classified as silty sand. It demonstrates strong collapsibility, with the collapsibility coefficient decreasing as water content increases. The critical water content for red sand to avoid collapsibility is 13%. The shear strength, internal friction angle, and cohesion of undisturbed and remolded red sand decrease with increasing water content. The critical water content for red sand to lose cohesion is 13%. The bearing capacity and deformation modulus of red sand decrease with increasing water content. Red sand exhibits a softening property, with a softening coefficient of 0.4. The water sensitivity of red sand can be attributed to the cementing effects of fine-grained clay minerals adhering to the surface of large particles or aggregating at particle contacts.
Multiphysics simulation of freezing and thawing granular media using material point method
Authors: Yu Jidu , Zhao Jidong , Zhao Shiwei , Liang Weijian 
Published: May 2024

Abstract
In this paper, a fully coupled thermo-hydro-mechanical material point method, applicable to liquid-saturated porous systems undergoing large deformations and phase transitions, is presented. A mathematical framework was established based on multiphasic mixture theory and fundamental physical conservation laws, rather than using phenomenological or semi-empirical equations. A fractional-step-based semi-implicit solution scheme was proposed to solve the coupled formulations within the framework of the generalized interpolation material point method. The proposed method was validated using several benchmark examples, including the talik closure and thaw consolidation. Its performance in simulating climate-driven large deformation problems was further demonstrated by simulating the settlement of a rigid footing on thawing ground. This paper presents an innovative and rigorous framework for predicting the impact of climate change on engineering practices.
Investigation of the effect of loading pulses on the ballast resilient modulus with SmartRock in a large-scale triaxial test
Authors: Huang Shihao , Qian Yu 
Published: May 2024

Abstract
Ballast resilient modulus is a key metric for assessing track resiliency and guiding railroad maintenance. Large-scale triaxial tests are used to determine the ballast resilient modulus and mechanical properties. Replicating complex train-induced loading pulses from field observations in a laboratory setting is challenging owing to technical limitations. Consequently, laboratory tests often employ simplified half-sine and haversine loading pulses with various rest intervals to simulate real-world conditions. However, the effects of different pulses on the obtained ballast resilient modulus remain unclear. In this study, large-scale triaxial tests were conducted using SmartRock sensors to investigate the effects of various cyclic loading pulses on the resilient modulus of the railroad ballast. A new index, called the cyclic loading duration ratio (CLDR), was introduced to categorize these pulses. The results revealed that the resilient modulus correlated with the CLDR, with its impact contingent upon the deviator stress. A CLDR value of 0.20 emerged as a critical threshold, yielding the lowest resilient modulus. Values below this threshold resulted in an increased resilient modulus owing to the consequential large axial acceleration. This study provides insights into the micromechanical resilience reactions of railroad ballast under diverse loading pulses and offers guidance for pulse selection in triaxial testing.
Application of fluid rheology models for milled woody biomass and non-recyclable municipal solid waste particles
Authors: Ikbarieh Abdallah , Lu Yimin , Zhao Yumeng , Dai Sheng 
Published: May 2024

Abstract
Biofuels from biomass and non-recyclable municipal solid waste (N-MSW) can potentially replace aviation fossil fuels. However, the cost-effectiveness is impeded by feedstock handling issues, such as unstable flow or jamming in hoppers and feeders. This issue can be solved mainly based on enhanced understanding of the rheology of biomass and N-MSW particles, which remains poorly understood. Leveraging discrete and continuum-based granular rheology models, in this study, we conduct industry-scale hopper flow testing of milled woody biomass, paper, cardboard, foam, thin film, and plastic particles, and investigate the potential of using fluid rheology models to characterize the hopper flow behavior. The hopper flow tests demonstrate different flow behaviors of tested materials, including fast flow, stable-to-unstable flow, and varying flow rates. Numerical simulation of hopper flow tests utilizing the Gudehus-Bauer hypoplastic model demonstrates good agreement with experimental data for the biomass and rigid plastic particles, and those using non-Newtonian fluid models exhibit promising agreement with experimental data with low computational cost. However, new fluid rheological models are required to capture the unstable and varying rate flows of highly compressible particles such as paper and foam. This study advances the knowledge on the rheology of particulate biomass and N-MSW materials for biofuel production.
Effects of slope topography on rock avalanche mobility and deposition: A 2-D discrete element method investigation
Authors: Xia Jiacheng , Jing Lu , Chen Jianfeng , Peng Ming 
Published: May 2024

Abstract
The impact of rock avalanches is a major concern in mountain areas. However, fundamental understanding and reliable prediction of the depositional area of rock avalanches remains inadequate. Here, an idealized numerical study of granular materials flowing down a slope is carried out using two-dimensional (2-D) discrete element method simulations. The effects of the slope geometry on the mobility and deposit morphology of the granular flow are studied in detail. It is found that the granular flow mobility increases with the curvature radius of the circular ramp, leading to a longer runout distance, which is explained from the viewpoint of energy transfer and dissipation. The results are expected to enhance understanding of the travel and deposition mechanisms of rock avalanches and other related geophysical flows.
Triggering and evolution of static liquefaction in submarine slopes with quasi-saturated sand
Authors: Tong S J , Huang M S , Shi Z H , Shen K M , Wang B 
Published: May 2024

Abstract
Liquefaction flow slides of submarine slopes with quasi-saturated sand have been frequently observed in engineering practice. That instability can be attributed to a decrease in resistant shear strength caused by static liquefaction. However, the triggering of static liquefaction in submarine slopes has received limited attention. To address this gap, a state-dependent constitutive model for quasi-saturated sand with entrapped air is employed that can represent the effects of compression and dissolution of gas accurately. Moreover, the soil model enables the evaluation of the triggering of static liquefaction based on second-order work. To study the triggering mechanism of static liquefaction, a submarine slope model is established using the material point method. The static liquefaction area is detected by the vanish of second-order work. Results indicate that static liquefaction initially arises at the slope surface and gradually expands towards the interior of the slope as the rapid loading at the top of the slope increases. Furthermore, the presence of entrapped gas within the slope can effectively enhance the resistance to slope instability caused by static liquefaction. It significantly alters both the location where static liquefaction is initially triggered and the subsequent evolution pattern, in comparison with saturated submarine slopes.
A review and evaluation of thermal conductivity model of compacted bentonite and its mixture
Authors: Ye W M , Shao C Y , Chen L 
Published: May 2024

Abstract
The thermal conductivity of bentonite plays a crucial role in analyzing the heat transfer process and determining the temperature field distribution within deep geological repositories. Despite considerable efforts in modeling the thermal conductivity of compacted bentonite and its mixtures, a comprehensive synthesis of these studies has not been previously undertaken. This research aimed to thoroughly review predictive models for the thermal conductivity of compacted bentonite and its mixtures, assessing their performance against a substantial dataset comprising 495 measurements of GMZ and MX80 bentonite. Through a systematic compilation and evaluation of seven models for compacted bentonite and three models for bentonite mixtures, the study identified TC2008 and LC2016 as the most accurate models for GMZ and MX80 compacted bentonite, respectively, whereas PT2021 emerged as the superior predictor for GMZ and MX80 bentonite mixtures. This exploration revealed the absence of a single, universally accurate model capable of predicting the thermal conductivities across all bentonite variants, highlighting the necessity for researchers to judiciously select the most fitting model for predicting the thermal conductivity of bentonite. Furthermore, we expressed the inherent limitations in current thermal conductivity models for compacted bentonite and its mixtures, and proposed directions for future inquiry in this domain.
Experimental study on compression behaviours of compacted sandy loam using a Modified State Surface Approach
Authors: Li Yixin , Cui Yujun , Geng Xueyu 
Published: May 2024

Abstract
It is essential to study the deformation of unsaturated soil to predict the settlement of constructed embankments and foundations under precipitation and external loadings. This study conducted suction-controlled and stress-controlled oedometer tests on compacted sandy loam. The void ratio and degree of saturation were measured to study the deformation behaviours of unsaturated soil. The acquired data were analyzed using a modified state surface approach (MSSA). It was found that for the samples with an identical initial state, a unique state surface can be employed to describe the change of void ratio in an e-σ
v’-s space, which consists of an elastic session and a plastic collapsible session. After yielding, the LC yield curve expands along the plastic collapsible surface with increasing loading or decreased suction, accompanied by irrecoverable plastic deformation. Along the hydraulic wetting paths (suction decreasing), the soil exhibits expansive deformation in the elastic surface but collapses into plastic collapsible after yielding. Differing from deformation behaviours, this study also demonstrated that the degree of saturation (S
r) cannot be plotted in a unique surface in S
r-σ
v’-s space regarding hydraulic wetting and mechanical compression. This can be interpreted by different mechanisms of increasing S
r by adsorbing water and mechanical compression.
Structural, soil-water, and dynamic characteristics of clay with different moisture and temperature histories
Authors: Zhang Lin , Han Zhong , Zou Weilie , Feng Huaiping 
Published: May 2024

Abstract
Variations in the hydro-mechanical properties of pavement subgrade soils are complex under long-term, repeated, and interlaced moisture and temperature (M-T) effects, such as wetting-drying (WD) and freeze-thaw (FT) processes. This study compares the soil structure, soil-water characteristic curves, and accumulated plastic strain (ɛ
p) of compacted Heilongjiang clay with three different M-T histories. Experimental results demonstrated that (i) after M-T actions, structural pores develop while textural pores shrink, leading to a reduction in the water retention capacity and an increase in the desaturation rate. Following the stabilization of the M-T effects, the soil structure and soil-water characteristics of specimens with different M-T histories become similar; (ii) at high moisture content (w), ɛ
p is more sensitive to moisture changes (including w and suction, s). Following the FT cycles, ε
p and ε
pa (the difference between the ε
p at 5000th and 3000th cyclic loading) become more sensitive to moisture changes; (iii) after M-T effects, the ε
pa-w relationship is nonlinear while the ε
pa-logs relationship is linear. Different M-T histories generated differences in only the ε
p at the beginning of the FT processes while such differences disappear after M-T effects have stabilized. The experimental data presented in this paper could prove valuable in understanding the behaviors of pavement soils under complex environmental conditions.
Study on rock energy evolution and constitutive model under water–rock interaction
Authors: Zhang H , Liu X L , Huang Z , Lu X L 
Published: May 2024

Abstract
To explore the degradation in rock mechanical properties due to water–rock interactions and formulate a nonlinear damage constitutive model for the entire stress–strain curve of rocks, experiments involving saturated, dry-wet cycling, and uniaxial compression tests were conducted on granite and siltstone. Based on energy theory, the energy evolution of the rock throughout the testing process was scrutinized. The range of the compaction stage was identified through the analysis of the dissipation energy change curve. A nonlinear damage constitutive model for rocks subjected to water-rock interactions was then devised, drawing on concepts from statistical damage mechanics. The findings indicated a progressive reduction in uniaxial compressive strength and elastic modulus due to water–rock interactions, while the Poisson’s ratio was observed to increase. The energy density curve under these conditions delineated four distinct phases: compaction energy dissipation, linear energy accumulation, pre-peak gradient increase, and post-peak sudden change. The introduction of the unit elastic strain energy density metric underscored the deteriorating effects from an energy standpoint. A nonlinear damage constitutive model, incorporating the compaction stage based on a coupled damage variable, was formulated. The predictions of this model closely matched the empirical data, thereby affirming its validity. This model provides an enhanced depiction of rock deformation and failure mechanisms under the influence of water–rock interactions.
Tunnel rockbursts induced by dynamic disturbances: mechanism and mitigation
Authors: Deng Jian , Gong Fengqiang , Zhu Hehua 
Published: May 2024

Abstract
Rockbursts are characterized by violent rock fractures and pose a significant threat to hard-rock tunnels, potentially resulting in casualties and damage to excavation spaces. Globally recognized as one of the least understood and most feared challenges in underground excavations, rockbursts are often triggered by dynamic disturbances such as engineering activities or nearby vibrations. This study conceptualizes rockbursts as dynamic buckling or instability issues inherent in rock structures. It specifically investigates the mechanism of tunnel rockbursts induced by ambient blasting. The derivation of the governing equation of motion, which incorporates shear deformation and rotary inertia of the rock column, results in coupled Mathieu equations. By employing the proposed numerical method, the conditions triggering rockburst were established using instability diagrams. The study examines the effects of static components, dynamic loading, and frequency on a tunnel example, revealing that the amplitude and frequency of dynamic disturbances are critical in influencing the occurrence of tunnel rockbursts through perturbation effects and parametric resonance mechanisms. These insights offer valuable understanding into the mechanisms, mitigation, and control of tunnel rockbursts.
Meta-contact analysis based on contact theory in three-dimensional discontinuous deformation analysis
Authors: Wang Xi , Wu Wei , Zhu Hehua 
Published: May 2024

Abstract
Accurate contact analysis between nonspherical blocks, such as polyhedral blocks, is crucial for modeling jointed rock masses. The Contact Theory provides a rigorous foundation for contact detection. However, designing a robust and efficient algorithm that conforms to the original Contact Theory remains challenging. This study introduces the meta-contact concept for polyhedral blocks, which corresponds to the contact cover on the entrance block of the Contact Theory. Using the meta-contact concept, contact type identification, determination of contact points and plans, and contact force calculation can be formulated while retaining the advantages of Contact Theory in dealing with irregular blocks with small edges and large penetration.
Numerical research method of rock slope with intermittent fractures based on parallel bond contact model
Authors: Yang Hongwei , Zhao Cheng , Xing Jinquan , Hu Tairan , Huang Lin , Chen Huiguan , Pan Haoyu 
Published: May 2024

Abstract
Within the domain of rock slopes characterized by intermittent fracturing, the fracture distribution and the mechanical properties of the interstitial rock bridges significantly influence the stability of the slope. The parallel bond contact model is advantageous in replicating the mechanical behavior of rock particles. This research introduces a numerical methodology for analyzing rock slopes with intermittent fractures using the parallel bond contact model. Initially, the model’s microscale parameters are refined through calibration with empirical data derived from macroscopic mechanical tests on rocks. Following this, the discrete element modeling software is employed to construct a detailed rock slope model. This model incorporates a smooth joint approach to define the intermittent fractures, enabling the creation of slope models with varying configurations of coplanar rock bridges and diverse rock types. The research methodologically investigates the mechanical properties and failure patterns of rock slopes under a spectrum of variable combinations. The findings reveal that slopes with multiple rock bridges demonstrate progressive failure and interlocking phenomena during their load-deformation cycles. These insights provide a foundational understanding for the analysis of catastrophic mechanisms and the stability assessment of rock slopes.