Pub Date : 2024-10-30DOI: 10.1016/j.sandf.2024.101532
Pongpipat Anantanasakul , Victor N. Kaliakin
This paper investigates shear banding as a possible failure mode for silt–clay transition soils under general three-dimensional stress conditions. Drained and undrained true triaxial tests with constant values were performed on tall prismatic specimens of such soils with systematically varying silt contents. Based on the values of critical plastic hardening modulus, shear banding does not govern the strength characteristics of the soils for values less than 0.2. For larger values, shear band formation is essentially critical as it takes place in the hardening regime of the stress–strain curves prior to the smooth peak failure points. An increase in silt content appears to move the onset of shear banding to lower levels of shear in the stress–strain relations of the silt–clay transition soils. It is also demonstrated that a non-associated constitutive model with a single hardening law is capable of accurately predicting the onset of shear banding in normally consolidated silt–clay transition soils based on bifurcation theory.
本文研究了淤泥-粘土过渡土在一般三维应力条件下可能的破坏模式--剪切带。在淤泥含量系统变化的此类土的高棱柱试样上进行了恒定 b 值的排水和不排水真三轴试验。根据临界塑性硬化模量值，当 b 值小于 0.2 时，剪切带并不影响土壤的强度特性。对于较大的 b 值，剪切带的形成基本上是临界的，因为它发生在应力-应变曲线的硬化阶段，在光滑的峰值破坏点之前。在淤泥-粘土过渡土壤的应力-应变关系中，淤泥含量的增加似乎会使剪切带的形成转移到较低的剪切水平。研究还证明，基于分岔理论，具有单一硬化规律的非关联构造模型能够准确预测正常固结的粉砂-粘土过渡土壤中剪切带的出现。
{"title":"Shear band analysis of silt-clay transition soils under three-dimensional stress-strain conditions","authors":"Pongpipat Anantanasakul , Victor N. Kaliakin","doi":"10.1016/j.sandf.2024.101532","DOIUrl":"10.1016/j.sandf.2024.101532","url":null,"abstract":"<div><div>This paper investigates shear banding as a possible failure mode for silt–clay transition soils under general three-dimensional stress conditions. Drained and undrained true triaxial tests with constant <span><math><mi>b</mi></math></span> values were performed on tall prismatic specimens of such soils with systematically varying silt contents. Based on the values of critical plastic hardening modulus, shear banding does not govern the strength characteristics of the soils for <span><math><mi>b</mi></math></span> values less than 0.2. For larger <span><math><mi>b</mi></math></span> values, shear band formation is essentially critical as it takes place in the hardening regime of the stress–strain curves prior to the smooth peak failure points. An increase in silt content appears to move the onset of shear banding to lower levels of shear in the stress–strain relations of the silt–clay transition soils. It is also demonstrated that a non-associated constitutive model with a single hardening law is capable of accurately predicting the onset of shear banding in normally consolidated silt–clay transition soils based on bifurcation theory.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101532"},"PeriodicalIF":3.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552411","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}
Pub Date : 2024-10-25DOI: 10.1016/j.sandf.2024.101505
Zhan-liang Wang , Wu-zhen Kang , Fu-quan Chen , Cheng Lin
A solution method for the determination of seismic passive earth pressures in narrow cohesive backfill behind gravity walls has been developed using the stress characteristics method. The stress characteristics method is combined with the pseudo-static method in the analysis to consider the effects of seismic forces. The failure mechanisms of backfill are complex when the backfill reaches its passive limit state. The stress characteristics method does not require pre-assumptions about the sliding surface and the plastic region of the backfill. This method automatically calculates the position of the sliding surface. The reliability and reasonableness of the proposed method are verified by comparing the sliding surface and seismic passive earth pressure calculated in this paper with the finite element calculation results, the existing experimental research results and the existing theoretical solution results. The effect of different parameters on seismic passive earth pressure is investigated by internal stress clouds of the backfill and the distribution of passive earth pressure on the retaining wall.
{"title":"Seismic passive earth pressures of narrow cohesive backfill against gravity walls using the stress characteristics method","authors":"Zhan-liang Wang , Wu-zhen Kang , Fu-quan Chen , Cheng Lin","doi":"10.1016/j.sandf.2024.101505","DOIUrl":"10.1016/j.sandf.2024.101505","url":null,"abstract":"<div><div>A solution method for the determination of seismic passive earth pressures in narrow cohesive backfill behind gravity walls has been developed using the stress characteristics method. The stress characteristics method is combined with the pseudo-static method in the analysis to consider the effects of seismic forces. The failure mechanisms of backfill are complex when the backfill reaches its passive limit state. The stress characteristics method does not require pre-assumptions about the sliding surface and the plastic region of the backfill. This method automatically calculates the position of the sliding surface. The reliability and reasonableness of the proposed method are verified by comparing the sliding surface and seismic passive earth pressure calculated in this paper with the finite element calculation results, the existing experimental research results and the existing theoretical solution results. The effect of different parameters on seismic passive earth pressure is investigated by internal stress clouds of the backfill and the distribution of passive earth pressure on the retaining wall.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101505"},"PeriodicalIF":3.3,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530177","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}
Pub Date : 2024-10-24DOI: 10.1016/j.sandf.2024.101530
Haotian Guo , Yuli Lin , Jinming Li , Chao Sun
In order to examine the principles governing the variation of dynamic characteristic parameters, including the damping ratio, dynamic modulus, and frozen soil backbone curve, under different negative temperature conditions, silty clays sourced from the Changchun region were selected for the research. Dynamic loading studies were carried out on silty clays under different negative temperature conditions using a temperature-controlled GDS dynamic triaxial machine. The results demonstrated that the lower the temperature, the higher the dynamic stress required to achieve the same dynamic strain. The inverse of the dynamic modulus is linearly related to the dynamic strain, and the intercept of the fitted line of the inverse of decreases with decreasing temperature. The damping ratio and ability to absorb vibration waves decrease as the temperature drops. As the temperature decreases, the maximum dynamic modulus gradually increases, and the maximum damping ratio has the opposite trend. The temperature correction formulas for the maximum dynamic modulus and maximum damping ratio of silty clay are proposed by correlation analysis method based on test data.
{"title":"Experimental study and correction of dynamic characteristic parameters of silty clay under negative temperature conditions","authors":"Haotian Guo , Yuli Lin , Jinming Li , Chao Sun","doi":"10.1016/j.sandf.2024.101530","DOIUrl":"10.1016/j.sandf.2024.101530","url":null,"abstract":"<div><div>In order to examine the principles governing the variation of dynamic characteristic parameters, including the damping ratio, dynamic modulus, and frozen soil backbone curve, under different negative temperature conditions, silty clays sourced from the Changchun region were selected for the research. Dynamic loading studies were carried out on silty clays under different negative temperature conditions using a temperature-controlled GDS dynamic triaxial machine. The results demonstrated that the lower the temperature, the higher the dynamic stress required to achieve the same dynamic strain. The inverse of the dynamic modulus <span><math><mrow><mn>1</mn><mo>/</mo><msub><mi>E</mi><mi>d</mi></msub></mrow></math></span> is linearly related to the dynamic strain, and the intercept of the fitted line of the inverse of <span><math><mrow><mn>1</mn><mo>/</mo><msub><mi>E</mi><mi>d</mi></msub></mrow></math></span> decreases with decreasing temperature. The damping ratio and ability to absorb vibration waves decrease as the temperature drops. As the temperature decreases, the maximum dynamic modulus gradually increases, and the maximum damping ratio has the opposite trend. The temperature correction formulas for the maximum dynamic modulus and maximum damping ratio of silty clay are proposed by correlation analysis method based on test data.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101530"},"PeriodicalIF":3.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530175","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}
Pub Date : 2024-10-24DOI: 10.1016/j.sandf.2024.101518
Sanjei Chitravel , Masahide Otsubo , Reiko Kuwano
Internal erosion involves the transport of soil particles from within or beneath a geotechnical structure due to seepage flow, influencing the subsequent mechanical and hydraulic behaviour of the soil. However, predicting changes in small-strain modulus () with eroded fines and varying principal stress directions can be challenging due to various factors related to soil fabric. The present study investigates the impact of seepage flow on , as well as the effect of principal stress rotation (PSR), of gap-graded soil with a fines content of 20%, using a novel erosion hollow cylindrical torsion shear apparatus. The erosion test results indicate that, regardless of density, the generally increases with seepage time. The trend of measured in the vertical and torsional directions varies significantly, as seepage is applied always downward, resulting in a different impact on the vertical and horizontal bedding planes. After a cycle of PSR, the induced torsional shear strain is found larger for the eroded specimens, while vertical strain decreases due to fine removal accompanied by seepage flow. In the PSR tests, the specimens subjected to erosion exhibit a greater reduction in compared to non-eroded specimens, with increasing the angles of principal stress direction. This reduction may be due to the inefficacy of the reinforced soil skeleton established by erosion against shearing. The distribution of fine particles and anisotropy induced by seepage flow contribute to non-trivial mechanical behaviour during principal stress rotation, particularly regarding small-strain shear modulus.
内部侵蚀是指由于渗流作用，土壤颗粒从岩土结构内部或下方迁移，从而影响土壤随后的机械和水力行为。然而，由于与土壤结构相关的各种因素，预测小应变模量（Gmax）随侵蚀细粒和不同主应力方向的变化具有挑战性。本研究使用新型侵蚀空心圆柱扭剪仪，研究了渗流对细粒含量为 20% 的间隙级配土壤的 Gmax 的影响以及主应力旋转（PSR）的影响。侵蚀试验结果表明，无论密度如何，Gmax 一般都会随着渗流时间的延长而增大。由于渗流始终向下进行，因此对垂直和水平基底面的影响不同，在垂直和扭转方向测量到的 Gmax 变化趋势也大不相同。经过一个 PSR 周期后，发现侵蚀试样的诱导扭转剪切应变较大，而垂直应变则由于伴随渗流的细粒去除而减小。在 PSR 试验中，受到侵蚀的试样与未受到侵蚀的试样相比，随着主应力方向角的增大，Gmax 的减小幅度更大。这种减小可能是由于侵蚀产生的加固土壤骨架无法有效抵抗剪切力。细颗粒的分布和渗流引起的各向异性导致了主应力旋转过程中的非三维机械行为，特别是在小应变剪切模量方面。
{"title":"The effect of suffusion on small strain shear modulus of gap-graded soil under principal stress rotation","authors":"Sanjei Chitravel , Masahide Otsubo , Reiko Kuwano","doi":"10.1016/j.sandf.2024.101518","DOIUrl":"10.1016/j.sandf.2024.101518","url":null,"abstract":"<div><div>Internal erosion involves the transport of soil particles from within or beneath a geotechnical structure due to seepage flow, influencing the subsequent mechanical and hydraulic behaviour of the soil. However, predicting changes in small-strain modulus (<span><math><mrow><msub><mi>G</mi><mrow><mi>max</mi></mrow></msub></mrow></math></span>) with eroded fines and varying principal stress directions can be challenging due to various factors related to soil fabric. The present study investigates the impact of seepage flow on <span><math><mrow><msub><mi>G</mi><mrow><mi>max</mi></mrow></msub></mrow></math></span>, as well as the effect of principal stress rotation (PSR), of gap-graded soil with a fines content of 20%, using a novel erosion hollow cylindrical torsion shear apparatus. The erosion test results indicate that, regardless of density, the <span><math><mrow><msub><mi>G</mi><mrow><mi>max</mi></mrow></msub></mrow></math></span> generally increases with seepage time. The trend of <span><math><mrow><msub><mi>G</mi><mrow><mi>max</mi></mrow></msub></mrow></math></span> measured in the vertical and torsional directions varies significantly, as seepage is applied always downward, resulting in a different impact on the vertical and horizontal bedding planes. After a cycle of PSR, the induced torsional shear strain is found larger for the eroded specimens, while vertical strain decreases due to fine removal accompanied by seepage flow. In the PSR tests, the specimens subjected to erosion exhibit a greater reduction in <span><math><mrow><mspace></mspace><msub><mi>G</mi><mrow><mi>max</mi></mrow></msub></mrow></math></span> compared to non-eroded specimens, with increasing the angles of principal stress direction. This reduction may be due to the inefficacy of the reinforced soil skeleton established by erosion against shearing. The distribution of fine particles and anisotropy induced by seepage flow contribute to non-trivial mechanical behaviour during principal stress rotation, particularly regarding small-strain shear modulus.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101518"},"PeriodicalIF":3.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530176","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}
Pub Date : 2024-10-22DOI: 10.1016/j.sandf.2024.101523
Tengyuan Zhao , Fenglin Shen , Ling Xu
Geotechnical properties, such as cohesion, pile drivability, rock strength, is one of the most important and indispensable input for design or analysis of geotechnical/geological engineering projects. Conventionally, these properties are obtained from laboratory experiments with well-prepared samples or well-designed experiments in-situ. Although direct measurements are generally accurate, they are often time-consuming and laborious, and acquisition of numerous measurements is often not available. This is especially true for medium- or small-sized projects. Alternatively, the properties of interest can be predicted from readily available indices by some machine learning (ML) methods, which has been applied to geotechnical engineering increasingly in recent years. Although ML methods perform reasonably well in predicting target geotechnical properties, all features considered subjectively relevant were often taken as input to the developed model. However, not all features contribute equally significant to the prediction. Involvement of irrelevant indices in an ML model would increase the model complexity, add additional difficulty in result interpretation, and introduce a risk of degrading the model’s generalization ability. Although these points have been well recognized in literature, only few studies carried out feature selection when ML methods are applied to geotechnical/geological engineering. This paper aims to alleviate this gap by offering a comprehensive review and comparison of commonly used ML methods, with consideration of various methods for feature selection. Selection of relevant features for the problem at hand also agrees well with the spirit of “data first practice central agenda” in data-centric geotechnics. Both simulated and real-life datasets are used to compare performance of the various ML methods in feature selection and prediction. Results show that fully Bayesian-Gaussian process regression (fB-GPR) outperforms other ML models.
岩土特性，如内聚力、可打桩性、岩石强度，是岩土/地质工程项目设计或分析中最重要且不可或缺的输入参数之一。传统上，这些特性都是通过实验室实验或精心设计的现场实验获得的。虽然直接测量通常比较准确，但往往费时费力，而且往往无法获得大量测量数据。这对于中小型项目来说尤其如此。另外，也可以通过一些机器学习（ML）方法，根据现成的指标来预测相关特性，近年来，这种方法已越来越多地应用于岩土工程中。尽管 ML 方法在预测目标岩土特性方面表现相当出色，但所有被认为主观相关的特征通常都被作为开发模型的输入。然而，并非所有特征对预测都有同样重要的贡献。将不相关的指标纳入 ML 模型会增加模型的复杂性，增加结果解释的难度，并有可能降低模型的泛化能力。虽然这些观点已在文献中得到充分认识，但在将 ML 方法应用于岩土工程/地质工程时，进行特征选择的研究却寥寥无几。本文旨在通过对常用的 ML 方法进行全面回顾和比较，并考虑各种特征选择方法，从而弥补这一不足。针对当前问题选择相关特征，也非常符合以数据为中心的岩土工程学中 "数据第一实践中心议程 "的精神。模拟数据集和实际数据集都用于比较各种多项式方法在特征选择和预测方面的性能。结果表明，完全贝叶斯高斯过程回归（fB-GPR）优于其他 ML 模型。
{"title":"Review and comparison of machine learning methods in developing optimal models for predicting geotechnical properties with consideration of feature selection","authors":"Tengyuan Zhao , Fenglin Shen , Ling Xu","doi":"10.1016/j.sandf.2024.101523","DOIUrl":"10.1016/j.sandf.2024.101523","url":null,"abstract":"<div><div>Geotechnical properties, such as cohesion, pile drivability, rock strength, is one of the most important and indispensable input for design or analysis of geotechnical/geological engineering projects. Conventionally, these properties are obtained from laboratory experiments with well-prepared samples or well-designed experiments in-situ. Although direct measurements are generally accurate, they are often time-consuming and laborious, and acquisition of numerous measurements is often not available. This is especially true for medium- or small-sized projects. Alternatively, the properties of interest can be predicted from readily available indices by some machine learning (ML) methods, which has been applied to geotechnical engineering increasingly in recent years. Although ML methods perform reasonably well in predicting target geotechnical properties, all features considered subjectively relevant were often taken as input to the developed model. However, not all features contribute equally significant to the prediction. Involvement of irrelevant indices in an ML model would increase the model complexity, add additional difficulty in result interpretation, and introduce a risk of degrading the model’s generalization ability. Although these points have been well recognized in literature, only few studies carried out feature selection when ML methods are applied to geotechnical/geological engineering. This paper aims to alleviate this gap by offering a comprehensive review and comparison of commonly used ML methods, with consideration of various methods for feature selection. Selection of relevant features for the problem at hand also agrees well with the spirit of “<em>data first practice central agenda</em>” in data-centric geotechnics. Both simulated and real-life datasets are used to compare performance of the various ML methods in feature selection and prediction. Results show that fully Bayesian-Gaussian process regression (fB-GPR) outperforms other ML models.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101523"},"PeriodicalIF":3.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530174","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}
Pub Date : 2024-10-21DOI: 10.1016/j.sandf.2024.101521
Osamu Kusakabe
This contribution is part of a series of invited papers on “A Review of the Author’s Own Seminal Contributions”. The paper describes the author’s 45 years of research experiences with a focus on foundation studies with physical modeling. Following some general statements on physical modeling, the facilities that the author utilized are described; and subsequently, the selected foundation problems that he tackled are explained mainly from physical modeling viewpoints. The selected problems cover shallow/ deep foundation stability problems and a few geoenvironmental issues, such as ground vibrations and piling at post-closure waste disposal sites. The outcomes of his research offered engineering solutions that society needs. The paper emphasizes the usefulness of the methodology of combining the theory of plasticity and physical modeling.
{"title":"Foundation studies with physical modeling","authors":"Osamu Kusakabe","doi":"10.1016/j.sandf.2024.101521","DOIUrl":"10.1016/j.sandf.2024.101521","url":null,"abstract":"<div><div>This contribution is part of a series of invited papers on “A Review of the Author’s Own Seminal Contributions”. The paper describes the author’s 45 years of research experiences with a focus on foundation studies with physical modeling. Following some general statements on physical modeling, the facilities that the author utilized are described; and subsequently, the selected foundation problems that he tackled are explained mainly from physical modeling viewpoints. The selected problems cover shallow/ deep foundation stability problems and a few geoenvironmental issues, such as ground vibrations and piling at post-closure waste disposal sites. The outcomes of his research offered engineering solutions that society needs. The paper emphasizes the usefulness of the methodology of combining the theory of plasticity and physical modeling.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101521"},"PeriodicalIF":3.3,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530178","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}
Pub Date : 2024-10-18DOI: 10.1016/j.sandf.2024.101526
Yuan-en Pang , Xu Li , Zu-yu Chen
In earth-rockfill dams, roadbeds, airports, and other embankment projects, gradation information serves as the basis for evaluating the quality and suitability of fill materials. Addressing the limitations of existing image-based contour recognition methods and machine learning approaches in recognizing small particle size ranges, this study establishes the first publicly available coarse-grained soil database including Yellow River Silt and Quartz Sand datasets, with particle sizes ranging from 0.075 to 20 mm, comprising a total of 22,380 images. Subsequently, a novel Convolutional Neural Network (CNN) architecture, the Searcher-Analyzer Network (SaNet), based on the Deep Residual Network (ResNet), was proposed to enhance the accuracy of gradation recognition by taking multiple images under a single gradation as input. Finally, the interpretability of the model was discussed through feature map visualization. The results demonstrate that SaNet achieves of 1.63 × 10−2 and of 0.995 for Yellow River Silt, and of 1.21 × 10−2 and of 0.992 for Quartz Sand. Concurrently, the additional computational time and storage requirements are only 3.5 % and 0.3 % more than those of ResNet, allowing the recognition of a single image to be completed within 10 ms. The findings of this study indicate that the proposed SaNet model can instantly achieve high accuracy in gradation recognition, meeting the demands for real-time, non-destructive gradation testing in related tasks.
{"title":"Recognizing gradations of coarse soils based on big artificial samples and deep learning","authors":"Yuan-en Pang , Xu Li , Zu-yu Chen","doi":"10.1016/j.sandf.2024.101526","DOIUrl":"10.1016/j.sandf.2024.101526","url":null,"abstract":"<div><div>In earth-rockfill dams, roadbeds, airports, and other embankment projects, gradation information serves as the basis for evaluating the quality and suitability of fill materials. Addressing the limitations of existing image-based contour recognition methods and machine learning approaches in recognizing small particle size ranges, this study establishes the first publicly available coarse-grained soil database including Yellow River Silt and Quartz Sand datasets, with particle sizes ranging from 0.075 to 20 mm, comprising a total of 22,380 images. Subsequently, a novel Convolutional Neural Network (CNN) architecture, the Searcher-Analyzer Network (SaNet), based on the Deep Residual Network (ResNet), was proposed to enhance the accuracy of gradation recognition by taking multiple images under a single gradation as input. Finally, the interpretability of the model was discussed through feature map visualization. The results demonstrate that SaNet achieves <span><math><mrow><mover><mrow><mrow><mi>MAE</mi></mrow></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math></span> of 1.63 × 10<sup>−2</sup> and <span><math><mrow><mover><mrow><msup><mi>R</mi><mn>2</mn></msup></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math></span> of 0.995 for Yellow River Silt, and <span><math><mrow><mover><mrow><mrow><mi>MAE</mi></mrow></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math></span> of<!--> <!-->1.21 × 10<sup>−2</sup> and <span><math><mrow><mover><mrow><msup><mi>R</mi><mn>2</mn></msup></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math></span> of 0.992 for Quartz Sand. Concurrently, the additional computational time and storage requirements are only 3.5 % and 0.3 % more than those of ResNet, allowing the recognition of a single image to be completed within 10 ms. The findings of this study indicate that the proposed SaNet model can instantly achieve high accuracy in gradation recognition, meeting the demands for real-time, non-destructive gradation testing in related tasks.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101526"},"PeriodicalIF":3.3,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530179","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}
Pub Date : 2024-10-17DOI: 10.1016/j.sandf.2024.101522
X. Pintado , S. Kumpulainen , E. Romero , J. Suriol , A. Lloret , R.C. Weber , B.N. Madhusudhan , A. Ferrari , J. Kim , K. Koskinen , V. Heino
Bentonites are going to be part of the Engineered Barrier System (EBS) in deep geological disposal facilities for the safe disposal of spent nuclear fuel. Some of these repositories might be constructed in tectonically active locations, and some other repository locations might have seismic risks in future related to climate changes (e.g. glaciations).
The damping ratio is one of the parameters considered in dynamic analysis, and it can be measured by different methods. In this work, the damping ratio was measured in two different bentonites with the resonant column device and in one of these bentonites, it was also measured with the hollow cylinder, simple shear and triaxial tests in unloading–reloading paths. The results are presented in Pintado et al. (2019; 2023). The tests were carried out at different laboratories.
The samples were compacted at different dry densities and degrees of saturation and tested with different confinement pressures and strain levels to study the influence of the shear strain, degree of saturation, dry density and confinement pressure and also the influence of the test method. The two studied bentonites had different plasticity indices which was also considered in the analysis.
The results showed a clear dependence of the damping ratio on the confinement pressure and the shear strain but not as clear on the degree of saturation, the dry density and the plasticity index. The damping ratio measured by the hollow cylinder test followed the tendency of the resonant column results. The triaxial test presented larger values of damping ratios than following the tendency of the hollow cylinder and resonant column tests. The simple shear test did not follow the tendency of the other tests, presenting lower damping ratio values. All tests presented large scatter.
{"title":"Evaluation of the damping ratio of compacted sodium and calcium bentonites in unsaturated conditions","authors":"X. Pintado , S. Kumpulainen , E. Romero , J. Suriol , A. Lloret , R.C. Weber , B.N. Madhusudhan , A. Ferrari , J. Kim , K. Koskinen , V. Heino","doi":"10.1016/j.sandf.2024.101522","DOIUrl":"10.1016/j.sandf.2024.101522","url":null,"abstract":"<div><div>Bentonites are going to be part of the Engineered Barrier System (EBS) in deep geological disposal facilities for the safe disposal of spent nuclear fuel. Some of these repositories might be constructed in tectonically active locations, and some other repository locations might have seismic risks in future related to climate changes (e.g. glaciations).</div><div>The damping ratio is one of the parameters considered in dynamic analysis, and it can be measured by different methods. In this work, the damping ratio was measured in two different bentonites with the resonant column device and in one of these bentonites, it was also measured with the hollow cylinder, simple shear and triaxial tests in unloading–reloading paths. The results are presented in Pintado et al. (2019; 2023). The tests were carried out at different laboratories.</div><div>The samples were compacted at different dry densities and degrees of saturation and tested with different confinement pressures and strain levels to study the influence of the shear strain, degree of saturation, dry density and confinement pressure and also the influence of the test method. The two studied bentonites had different plasticity indices which was also considered in the analysis.</div><div>The results showed a clear dependence of the damping ratio on the confinement pressure and the shear strain but not as clear on the degree of saturation, the dry density and the plasticity index. The damping ratio measured by the hollow cylinder test followed the tendency of the resonant column results. The triaxial test presented larger values of damping ratios than following the tendency of the hollow cylinder and resonant column tests. The simple shear test did not follow the tendency of the other tests, presenting lower damping ratio values. All tests presented large scatter.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101522"},"PeriodicalIF":3.3,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445912","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}
Pub Date : 2024-10-15DOI: 10.1016/j.sandf.2024.101524
Gaowen Zhao , Tao Wu , Guanzhou Ren , Dongyang Yan , Zhen Zhu , Shijun Ding , Mei Shi , Henghui Fan
Dispersive soil is a common problem soil in engineering projects, which has the potential risk of causing serious engineering failures. In this paper, calcined waste phosphorus slag (CPS) was chosen to enhance the mechanical properties and reduce soil dispersivity. Dispersive soil samples with 1 % to 10 % CPS content were prepared and cured for 0 to 28 days. The dispersivity identification test was used to assess soil sample dispersivity. The compressive and tensile strength, conductivity, and pH were determined for the soil. Microstructural and mineral composition were analyzed using SEM/EDS, TG/DTG, and XRD analysis. The natural dispersive soil was selected to verify the effect of CPS in improving soil. Experiments show that the CPS inhibits soil dispersivity and converts it into non-dispersive soil. Both compressive and tensile strength increases significantly with the increase in the content of CPS and curing time. The tensile strength of the soil samples cured for 28 days increased by about 76 % and the compressive strength by about 61 % as the mixed content of CPS was increased from 1 % to 10 %. Results show that CPS can improve the strength and modify the dispersivity of soil, its optimal mixing content is 5 %. In addition, using CPS in dispersive soil could also solve the disposal problem of phosphate slag, which is a win-to-win solution.
{"title":"Modifying behavior of calcined waste phosphorus slag on the dispersivity and mechanical properties of dispersive soil","authors":"Gaowen Zhao , Tao Wu , Guanzhou Ren , Dongyang Yan , Zhen Zhu , Shijun Ding , Mei Shi , Henghui Fan","doi":"10.1016/j.sandf.2024.101524","DOIUrl":"10.1016/j.sandf.2024.101524","url":null,"abstract":"<div><div>Dispersive soil is a common problem soil in engineering projects, which has the potential risk of causing serious engineering failures. In this paper, calcined waste phosphorus slag (CPS) was chosen to enhance the mechanical properties and reduce soil dispersivity. Dispersive soil samples with 1 % to 10 % CPS content were prepared and cured for 0 to 28 days. The dispersivity identification test was used to assess soil sample dispersivity. The compressive and tensile strength, conductivity, and pH were determined for the soil. Microstructural and mineral composition were analyzed using SEM/EDS, TG/DTG, and XRD analysis. The natural dispersive soil was selected to verify the effect of CPS in improving soil. Experiments show that the CPS inhibits soil dispersivity and converts it into non-dispersive soil. Both compressive and tensile strength increases significantly with the increase in the content of CPS and curing time. The tensile strength of the soil samples cured for 28 days increased by about 76 % and the compressive strength by about 61 % as the mixed content of CPS was increased from 1 % to 10 %. Results show that CPS can improve the strength and modify the dispersivity of soil, its optimal mixing content is 5 %. In addition, using CPS in dispersive soil could also solve the disposal problem of phosphate slag, which is a win-to-win solution.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101524"},"PeriodicalIF":3.3,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442212","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}
Pub Date : 2024-10-10DOI: 10.1016/j.sandf.2024.101520
Tian-Gang Lan , Ling Xu , Shi-Feng Lu
Many geotechnical failures are associated with degradation of the soil strength over time. The time-dependency behavior of unsaturated loess is often required to evaluate the long-time behavior of geotechnical engineering in loess areas. To investigate such strain rate response and stress relaxation behavior of intact loess, a series of oedometric compression and relaxation tests were conducted under different suctions and strain rates. Water retention behaviors and microstructures were also measured to characterize the tested loess. The more rapid strain rate, leading to larger yield stress at relatively low suctions (0 and 50 kPa) and roughly paralleled one-dimensional normal compression lines (1D-NCL) conformed to the isotache approach. In contrast, the weakening effect of a more rapid strain rate on the clay cementation, resulted in smaller yield stress when the suction was larger than 100 kPa, which was an apparent deviation from the conception of the isotache. The reason might be that the microstructure developed during the long term (slow strain rate) under the relatively larger suction, which may increase the inter-particle bonding and structural strength. The relaxation behavior of unsaturated loess depended on suction and prerelaxation stress, which cannot be well described by the model with a soil constant viscosity Iv. The results of two viscous effects (rate-dependency and relaxation) in loess demonstrated that they could not altogether be explained within the isotache concept.
许多岩土工程的失效都与土壤强度随时间的推移而下降有关。要评估黄土地区岩土工程的长期行为，往往需要研究非饱和黄土的时间依赖行为。为了研究完整黄土的应变率响应和应力松弛行为，我们在不同吸力和应变率条件下进行了一系列气压压缩和松弛试验。此外，还测量了试验黄土的保水行为和微观结构。在相对较低的吸力（0 和 50 kPa）和大致平行的一维法向压缩线（1D-NCL）下，较快的应变速率导致较大的屈服应力，符合等压法。相反，当吸力大于 100 kPa 时，较快的应变速率对粘土胶结的削弱作用导致屈服应力较小，这明显偏离了等压法的概念。原因可能是在相对较大的吸力下，微观结构在长期（慢应变速率）过程中形成，这可能会增加颗粒间的结合力和结构强度。非饱和黄土的松弛行为取决于吸力和松弛前应力，而土壤恒定粘度 Iv 模型无法很好地描述这一点。黄土中两种粘性效应（速率依赖性和松弛）的结果表明，它们不能完全用等缓概念来解释。
{"title":"Effect of suction on time-dependent behavior of intact loess under oedometric conditions: Strain rate dependency and stress relaxation","authors":"Tian-Gang Lan , Ling Xu , Shi-Feng Lu","doi":"10.1016/j.sandf.2024.101520","DOIUrl":"10.1016/j.sandf.2024.101520","url":null,"abstract":"<div><div>Many geotechnical failures are associated with degradation of the soil strength over time. The time-dependency behavior of unsaturated loess is often required to evaluate the long-time behavior of geotechnical engineering in loess areas. To investigate such strain rate response and stress relaxation behavior of intact loess, a series of oedometric compression and relaxation tests were conducted under different suctions and strain rates. Water retention behaviors and microstructures were also measured to characterize the tested loess. The more rapid strain rate, leading to larger yield stress at relatively low suctions (0 and 50 kPa) and roughly paralleled one-dimensional normal compression lines (1D-NCL) conformed to the isotache approach. In contrast, the weakening effect of a more rapid strain rate on the clay cementation, resulted in smaller yield stress when the suction was larger than 100 kPa, which was an apparent deviation from the conception of the isotache. The reason might be that the microstructure developed during the long term (slow strain rate) under the relatively larger suction, which may increase the inter-particle bonding and structural strength. The relaxation behavior of unsaturated loess depended on suction and prerelaxation stress, which cannot be well described by the model with a soil constant viscosity <em>I<sub>v</sub></em>. The results of two viscous effects (rate-dependency and relaxation) in loess demonstrated that they could not altogether be explained within the isotache concept.</div></div>","PeriodicalId":21857,"journal":{"name":"Soils and Foundations","volume":"64 6","pages":"Article 101520"},"PeriodicalIF":3.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418143","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}
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