Soils and Foundations最新文献_第2页

Evaluation of frost heave model using measured values for temperature and water intake rate near the freezing front

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2025.101570

Takeshi Ishizaki , Satoshi Nishimura

Many frost heave theories and models have been proposed to explain the frost heave phenomenon. In the present study, systematic frost heave experiments were conducted under various temperature gradients and freezing rates, and the relationships between the water intake rate and the freezing front, freezing rate, temperature gradient in the frozen zone, and temperature of the ice lens growth surface were investigated. The experimental results showed that there is a linear relationship among the water intake rate, freezing rate, and temperature gradient, and that there is also a linear relationship between the water intake rate and the temperature of the ice lens growth surface. Based on these findings, the validity of the existing frost heave models was evaluated. The results of this study revealed that the water intake rate to the freezing front cannot be expressed only by the temperature gradient in the frozen fringe. In addition, a model in which the rate of the water intake into the ice lens is determined by the hydrodynamic resistance of the water flow in the frozen fringe cannot explain the experimental results well. With a kinetic model, in which the water intake rate is determined by the chemical potential difference between the ice lens and the nearby water film, it was found that the calculated results and the actual measurement results corresponded well when the self-diffusion coefficient of the water film near the ice lens was used as a fitting parameter.

{"title":"Evaluation of frost heave model using measured values for temperature and water intake rate near the freezing front","authors":"Takeshi Ishizaki , Satoshi Nishimura","doi":"10.1016/j.sandf.2025.101570","DOIUrl":"10.1016/j.sandf.2025.101570","url":null,"abstract":"<div><div>Many frost heave theories and models have been proposed to explain the frost heave phenomenon. In the present study, systematic frost heave experiments were conducted under various temperature gradients and freezing rates, and the relationships between the water intake rate and the freezing front, freezing rate, temperature gradient in the frozen zone, and temperature of the ice lens growth surface were investigated. The experimental results showed that there is a linear relationship among the water intake rate, freezing rate, and temperature gradient, and that there is also a linear relationship between the water intake rate and the temperature of the ice lens growth surface. Based on these findings, the validity of the existing frost heave models was evaluated. The results of this study revealed that the water intake rate to the freezing front cannot be expressed only by the temperature gradient in the frozen fringe. In addition, a model in which the rate of the water intake into the ice lens is determined by the hydrodynamic resistance of the water flow in the frozen fringe cannot explain the experimental results well. With a kinetic model, in which the water intake rate is determined by the chemical potential difference between the ice lens and the nearby water film, it was found that the calculated results and the actual measurement results corresponded well when the self-diffusion coefficient of the water film near the ice lens was used as a fitting parameter.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 1","pages":"Article 101570"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of freezing and thawing processes in clay with freeze-induced compression (FIC) model

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2024.101559

Satoshi Nishimura , Mingxuan Liang , Chuangxin Lyu

Fine-grained soils generally exhibit significant permanent compression due to freezing and thawing cycles. The nature of this compression was explored through the numerical analysis of two series of freezing (and thawing) experiments involving a wide range of temperature gradients (0.04–5 °C/mm) performed under K₀ conditions. A submodel that describes a state-dependent plastic volumetric strain rate during freezing and thawing, originally developed by Nishimura (2021), was employed for the fully Thermo-Hydro-Mechanically (THM) coupled Finite Element (FE) analysis. The submodel, called the Freeze-Induced Compression (FIC) module, works as an add-in to any elasto-plastic frozen soil model developed under a THM framework, and can be turned on or off according to the need. The elasto-plastic model for frozen/unfrozen states was reappraised and re-formulated such that all parameter values could be determined from conventional frozen/unfrozen tests. This paper illustrates the model/module implementation, as well as its effectiveness in describing both slow frost heave tests and fast repeated freeze–thaw cyclic tests. In the latter, the analysis with and without the FIC module indicated that macroscopic, inter-element water transfer alone plays only a secondary role in causing cumulative permanent volumetric strain. This insight highlights the need to implement an explicit module to describe freeze-induced compression, as is done in the present study.

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引用次数: 0

Convolutional neural network prediction of the particle size distribution of soil from close-range images

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2025.101575

Enrico Soranzo, Carlotta Guardiani, Wei Wu

Accurate soil particle size distributions are essential for various geotechnical applications. In this study, we propose a convolutional neural network approach for predicting the particle size distribution using soil image analysis. Our model is trained on a diverse dataset of soil samples ranging from clayey silt to gravel. We employed transfer learning by using MobileNet pre-trained on ImageNet and adding additional layers to fine-tune the model for our specific task. The soil images were captured under standardised lab conditions using a dark chamber with constant lighting to ensure consistency. We implemented the model in Python and explored various neural network architectures, image resolutions and data augmentation techniques to optimise performance. The model predicts the particle size distribution through two parameters derived from the Weibull distribution. Our approach offers instantaneous predictions and demonstrates robustness across a wide range of soil types. We outperform previous studies by incorporating geotechnical classification and predicting the entire particle size distribution curve. Additionally, we applied explainable artificial intelligence techniques to enhance the transparency and interpretability of the model’s predictions. Our findings highlight the effectiveness of the model and provide valuable insights into the relationship between soil image features and particle size characteristics.

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引用次数: 0

Long-term settlement behavior of peat after unloading and applicability of isotach law

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2024.101560

Nobutaka Yamazoe , Satoshi Nishimura , Hiroyuki Tanaka , Toshihiro Ogino , Taishi Kochi

Preloading is commonly adopted to minimize the post-construction residual settlement in soft peat grounds. However, non-negligible long-term settlement can still occur during the service period of the overlying structures, posing a challenge to infrastructural maintenance. It is difficult to predict the settlement in a preloaded and then reloaded ground with a conventional creep analysis using the coefficient of secondary consolidation, C_αe. This is because the determination of its value can be subjective owing to the limited observation timescale in both the field and the laboratory, which reflects the lingering effects of the previous loading history. Thus, each value determined for C_αe is condition-specific and cannot be considered as an inherent material property. This paper investigates the viscosity characteristics of preloaded peat through long-term consolidation tests, with a particular focus on the validity of the isotach law in explaining the strain-rate effect. It is found that the peat behavior follows the isotach rule even during unloading when the overconsolidation ratio (OCR) is smaller than 1.5. The theory based on the isotach law can describe the general reloading behavior with a constant C_αe value unique to each peat, when C_αe is reappraised by applying the strain rate, rather than the conventional void ratio (e) – log time relationship. The paper also discusses how the preloading effect can be evaluated from the settlement time history during construction, giving adequate care to some important features of peat, such as the significant decrease in permeability upon consolidation.

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引用次数: 0

Failure mechanics mechanisms and permeability stage evolution of limestone considering wave velocity and failure surface characteristics

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2025.101577

Genshui Wu , Weijian Yu , Bao Pan , Chuangfeng Fang , Hanxiao Guo , Chao Zhang

This research aims to investigate the impact of seepage conditions on the macroscopic and microscopic failure mechanics mechanisms of deep coal seam floor rock mass. The deep coal seam mining floor rock mass in North China has been penetrated by groundwater for a long period in a high-temperature and high-pressure environment, and its mechanical behavior is complicated and diversified. The macro- and micro-mechanical behavior of rock failure under seepage conditions was investigated in this work on deep floor rock strata using experimental methods such as rock mechanics, wave velocity, and nuclear magnetic resonance. The results demonstrate that the original cracks in thin limestone are more developed and have a gully-like structure at the mesoscopic scale than those in Ordovician limestone. According to the nuclear magnetic results, as the confining pressure increases, the initial water-conducting fissures and expanded cracks in the thin limestone may be constricted or closed. Macroscopically, under the action of stress and seepage in different types of rocks, fissures provide the main seepage channels. Due to the confining pressure, the pores are compressed and the permeability decreases significantly. Because rock permeability varies with confining pressure and axial pressure, there is a stress threshold for penetration mutation at each stage. The linear and nonlinear stage evolution characteristics of deep rock permeability and stress with confining pressure are established. The confining pressure affects the internal pore and crack structure of the rock, generating complex seepage network channels and causing changes in permeability properties. The research results provide a scientific foundation and theoretical support for the safe design and sustainable development of underground engineering.

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引用次数: 0

Experiments for the role of sliding connection in rigid faced GRS walls under transverse relative settlement

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2024.101557

Mohan Krishna Kolli, Amit Prashant

The transverse relative settlement of reinforced fill and fascia induces reinforcement loads additional to service loads in Geosynthetic Reinforced Soil (GRS) Walls. The fascia-reinforcement connections need due attention in such conditions for both strength and serviceability considerations. A sliding connection is an alternative to avoid the buildup of high reinforcement connection loads under the relative settlement. 1-g model tests were carried out in an in-house developed relative settlement simulator tank on full-height panel rigid fascia (RF) GRS walls with two types of conventional connection systems. The sliding connection system was developed and proposed for RF-GRS walls, and its performance was assessed under the relative settlement of fill. In RF-GRS walls with conventional connection systems, the maximum tensile strains increased more than 200 times in bottom reinforcement layers under the relative settlement of 0 to 200 mm compared to the end of the construction. The developed sliding connection systems reduced the stress concentrations at the connection and allowed almost free settlement of the fill relative to the fascia. The maximum reinforcement strains were reduced up to 50 times compared to conventional non-sliding connections under the relative settlement of 0 to 200 mm. Hence, the sliding connection systems are recommended in conditions where the relative settlement of fascia and fill is expected to affect RF-GRS walls’ performance.

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引用次数: 0

Experimental study on thermal conductivity and microscopic characterization of sandy clay in deep buried formation

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2024.101565

Yi Cao , Yansen Wang , Chuanxin Rong , Hao Li , Bin Wang , Xin Shi , Jie Zhang

The thermal conductivity of soil is a key factor influencing the heat transfer process and temperature distribution, which has significant implications for the design and implementation of freezing methods in geotechnical engineering. To address the challenge of freezing the deeply buried sandy clay layer using the freezing method in the drilling wells of the Huainan-Huaibei mining area, experimental research was conducted on the thermal conductivity of sandy clay and its microstructure. Utilizing the transient plane source method, variations in thermal conductivity with water content, dry density, sand content, and temperature were observed, revealing the patterns and mechanisms underlying these changes. The findings indicate that the thermal conductivity of frozen sandy clay mainly undergoes three stages of temperature variation. During the rapid increase phase (Ⅱ), the thermal conductivity rises sharply with decreasing temperature, exhibiting a “leap” trend. As the water content increases, the range of the thermal conductivity leap gradually narrows. When the water content increases from 15 % to 22.5 %, the corresponding leap range decreases to 0 ∼ -5℃. Microstructural parameters quantitatively reflect the intrinsic reasons for changes in soil thermal conductivity from a microscopic perspective, indicating that these characteristics significantly affect its thermal conductivity.

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引用次数: 0

Microscopic investigation of the occurring process of contact erosion

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2024.101555

Yubo Li , Guo Yu , Lei He , Ying Cui

Sand particles subjected to seepage can cause contact erosion because of particle migration. A visible seepage system packed with transparent sand optically matched oil, and a planar laser-induced fluorescence technique was used to visually study mechanisms during seepage-induced contact erosion. During the visualization experiments, two distinct contact erosion phenomena were observed. The first phenomenon is the common erosion phenomenon, which occurs in the entire sample range; it primarily manifests as the movement and migration of particles under the influence of the fluid, resulting in the loss of fine particles. The second phenomenon occurs in local areas of the sample and is characterized by particles being too large to pass through the pores; this leads to pore clogging, subsequently altering the seepage path and reducing the flow velocity. In addition, the effects of the hydraulic gradient and particle size on flow velocity and particle migration are analyzed. Preferential seepage paths are critical paths in the development of contact erosion. The force characteristics of the particles were investigated based on three types of instability modes and fitting curves to determine the stability of the soil structure considering the flow velocity and particle size. The findings in this study are through a visual experiment method to explain the instability modes and mechanism of particles in contact erosion and understand the relationship between particle migration and flow velocity.

{"title":"Microscopic investigation of the occurring process of contact erosion","authors":"Yubo Li , Guo Yu , Lei He , Ying Cui","doi":"10.1016/j.sandf.2024.101555","DOIUrl":"10.1016/j.sandf.2024.101555","url":null,"abstract":"<div><div>Sand particles subjected to seepage can cause contact erosion because of particle migration. A visible seepage system packed with transparent sand optically matched oil, and a planar laser-induced fluorescence technique was used to visually study mechanisms during seepage-induced contact erosion. During the visualization experiments, two distinct contact erosion phenomena were observed. The first phenomenon is the common erosion phenomenon, which occurs in the entire sample range; it primarily manifests as the movement and migration of particles under the influence of the fluid, resulting in the loss of fine particles. The second phenomenon occurs in local areas of the sample and is characterized by particles being too large to pass through the pores; this leads to pore clogging, subsequently altering the seepage path and reducing the flow velocity. In addition, the effects of the hydraulic gradient and particle size on flow velocity and particle migration are analyzed. Preferential seepage paths are critical paths in the development of contact erosion. The force characteristics of the particles were investigated based on three types of instability modes and fitting curves to determine the stability of the soil structure considering the flow velocity and particle size. The findings in this study are through a visual experiment method to explain the instability modes and mechanism of particles in contact erosion and understand the relationship between particle migration and flow velocity.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 1","pages":"Article 101555"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Heating-induced stabilization of weak clayey soils: A model incorporating pore water evaporation

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2025.101576

Yeong Jin Lee, Kang Il Lee, Tae Jun Cho

To strengthen a problematic clayey soil foundation, we proposed a heating system utilizing a modified heat transfer equation that considers the rapid evaporation of pore water due to high temperatures and accounts for latent heat. The modified equation was compared with results from commercial software and indoor model experiments, with its parameters evaluated through statistical and sensitivity analyses. The results demonstrated that the changes in parameters over time due to pore water evaporation and latent heat transfer exhibited behavior similar to the experimental results. Additionally, the sensitivity analysis revealed that the initial temperature condition exhibited the highest sensitivity at 18.44 %, while the bulk density showed the lowest sensitivity at 0.18 %. Therefore, the accurate temperature measurement for initial conditions is necessary for precise heat transfer analysis using the modified equation. Moreover, parameters such as water content, clay content, and shrinkage ratio should be determined through precise experiments, although applying average values yielded results within an error range of approximately 7 %. Finally, the experimental results showed a 267 % increase in resistance before and after heating to 600 ℃ in the cone penetration test.

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引用次数: 0

Efficient and accurate methodologies for MCS-based probabilistic analysis of tunnel face stability

IF 3.3 2区工程技术 Q2 ENGINEERING, GEOLOGICAL

Soils and Foundations

Pub Date : 2025-02-01 DOI: 10.1016/j.sandf.2024.101563

Bin Li, Yong-Kai Shen, Yuan-Sheng Lan

This paper proposes two strategies to perform efficient and accurate MCS-based probabilistic analysis of tunnel face stability. The first strategy takes the samples that have been evaluated by three-dimensional (3D) numerical simulations as classifiers to evaluate the MCS samples generated from the statistical parameters of uncertain variables. The number of 3D simulations can be significantly reduced to only 1 % or even 1‰ because most MCS samples are evaluated by the classifiers. This method is accurate because no approximation has been made in the evaluation process. The second strategy uses a previously established training dataset to construct an ensemble of metamodels to classify the MCS samples. Backpropagation Neural Network (BP) is utilized to construct a regression metamodel to predict the safety factors of each sample; the samples that are predicted to be near the limit state will be further evaluated by an adaptive classification metamodel constructed by the combination of K-Nearest Neighbor (KNN) and Support Vector Machine (SVM). KNN is used to search k training samples that have the smallest distances with the unknown sample, whereas SVM is used to construct a classification model to classify this sample using the k training samples. This strategy is much more efficient since a probabilistic analysis can be completed within a few seconds. Several illustrative examples are used to demonstrate the applications. Results show that the failure probabilities predicted by the ensemble of metamodels compare well with those determined according to direct MCS-based 3D numerical simulations, implying that the ensemble of metamodels is also accurate.

{"title":"Efficient and accurate methodologies for MCS-based probabilistic analysis of tunnel face stability","authors":"Bin Li, Yong-Kai Shen, Yuan-Sheng Lan","doi":"10.1016/j.sandf.2024.101563","DOIUrl":"10.1016/j.sandf.2024.101563","url":null,"abstract":"<div><div>This paper proposes two strategies to perform efficient and accurate MCS-based probabilistic analysis of tunnel face stability. The first strategy takes the samples that have been evaluated by three-dimensional (3D) numerical simulations as classifiers to evaluate the MCS samples generated from the statistical parameters of uncertain variables. The number of 3D simulations can be significantly reduced to only 1 % or even 1‰ because most MCS samples are evaluated by the classifiers. This method is accurate because no approximation has been made in the evaluation process. The second strategy uses a previously established training dataset to construct an ensemble of metamodels to classify the MCS samples. Backpropagation Neural Network (BP) is utilized to construct a regression metamodel to predict the safety factors of each sample; the samples that are predicted to be near the limit state will be further evaluated by an adaptive classification metamodel constructed by the combination of K-Nearest Neighbor (KNN) and Support Vector Machine (SVM). KNN is used to search <em>k</em> training samples that have the smallest distances with the unknown sample, whereas SVM is used to construct a classification model to classify this sample using the <em>k</em> training samples. This strategy is much more efficient since a probabilistic analysis can be completed within a few seconds. Several illustrative examples are used to demonstrate the applications. Results show that the failure probabilities predicted by the ensemble of metamodels compare well with those determined according to direct MCS-based 3D numerical simulations, implying that the ensemble of metamodels is also accurate.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"65 1","pages":"Article 101563"},"PeriodicalIF":3.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0