Transportation Geotechnics最新文献

{"title":"Experimental and numerical based model formulation for estimation of subgrade resilient modulus using the repeated load CBR test considering in situ state of stress","authors":"","doi":"10.1016/j.trgeo.2024.101331","DOIUrl":"10.1016/j.trgeo.2024.101331","url":null,"abstract":"<div><p>Characterizing subgrade in terms of resilient modulus is a crucial aspect of flexible pavement design. This paper proposes a methodology and predictive model to estimate the resilient modulus with better consideration of subgrade soils’ in situ stress state using a simple Repeated Load CBR (RLCBR) test. RLCBR tests were conducted on eight subgrade soils at three moisture contents. Numerical studies were conducted by simulating the CBR test in the commercial package LS-DYNA® to understand the stress state under plunger loading concerning field conditions. A new model was proposed for the characterization of subgrade soils based on laboratory RLCBR tests and the FEM, considering the stress state experienced by subgrade soils in the field. The proposed model was validated using data from four other soils and showed good agreement. The study model showed a better predictive capacity for the low plastic subgrade soils than previously developed models. Practicing engineers can use the developed model for estimating the subgrade resilient modulus at the recommended stress state for mechanistic pavement design while understanding the soil’s load-deformation behavior.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time pavement surface crack detection based on lightweight semantic segmentation model","authors":"","doi":"10.1016/j.trgeo.2024.101335","DOIUrl":"10.1016/j.trgeo.2024.101335","url":null,"abstract":"<div><p>Efficient and accurate pavement surface crack detection is crucial for analyzing pavement survey data. To achieve this goal, an improved lightweight semantic segmentation model based on BiSeNetv2, utilizing the detail branch, the semantic branch, and the guided aggregation module, is refined for automatic pavement surface crack detection. With the detail branch and the semantic branch, the low-level details and the high-level semantic context of pavement surface crack can be represented. Taking advantage of the guided aggregation module, the low-level and high-level crack features are mutually connected and fused. The gradient-weighted class activation mapping (Grad-CAM) is adopted to visualize the details of the evolution of crack feature extraction, fusion, and representation. Based on the evaluation results, the proposed lightweight model demonstrates its effectiveness and robustness in accurately segmenting pavement surface crack. Maximumly, it is 10.14% higher than the other model on F1 score, indicating its great potential for pavement crack detection.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of the utilization of cement-treated geotextile as a reinforcement element for highway base layer under cyclic loading","authors":"","doi":"10.1016/j.trgeo.2024.101333","DOIUrl":"10.1016/j.trgeo.2024.101333","url":null,"abstract":"<div><p>This study conducted large-scale cyclic loading experiments on the base layer overlying a weak subgrade soil. Geotextile and cement-treated geotextile were utilized to reinforce the base material and to separate the interface of soils between the base layer and the subgrade. The results obtained from the repeated loading tests using geotextile and cement-treated geotextile were analyzed and evaluated in terms of some benchmark indicators such as total deformation, permanent deformation, elastic deformation, percentage of elastic deformation, traffic benefit ratio (TBR), elastic modulus (M_R), improvement factor (I_f), and rut depth reduction ratio (RDR). Based on the experimental results, the use of cement-treated geotextile as a base layer reinforcement element or as an interfacial separation element demonstrated better performance compared to the use of geotextile. Utilization of a cement-treated geotextile as both reinforcement and separation element resulted in an RDR value of 49.26 % after 5000 cycles. Additionally, using a cement-treated geotextile for both reinforcement and separation increased the TBR value to 14.62 at 27 mm deformation, decreased the permanent deformation value from 53.67 mm to 27.23 mm, and approached approximately 2 improvement factor values, compared to using the geotextile solely for separation.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time detection of the lateral resistance of ballast bed during track realigning in tamping: A novel test method based on track shifting operation","authors":"","doi":"10.1016/j.trgeo.2024.101332","DOIUrl":"10.1016/j.trgeo.2024.101332","url":null,"abstract":"<div><p>Real-time detection of the mechanical state of ballast bed during the tamping operation in railway maintenance is of great significance for improving the effectiveness of operations. In this study, a novel test method named the track shifting test was proposed based on the track realigning operation of the tamping vehicle. The track panel was pushed by the shifting device. Moreover, the lateral resistance of ballast bed was reflected through easily measured indexes. An accurate coupling model of the shifting device and the ballasted track was constructed. Based on the model, the mechanical response of ballast and the track panel induced by the shifting load was analyzed. Results indicated that at an effective loading displacement of <span><math><mrow><mn>2</mn><mrow><mspace></mspace><mtext>mm</mtext></mrow></mrow></math></span>, the lateral resistance of ballast bed within a detectable range of up to five sleepers can be inverted by the shifting force and the displacement of sleepers. A machine learning model was established to obtain the mapping relationship between the shifting force, the displacement of sleepers, and the lateral resistance of ballast bed. Therefore, real-time detection of the lateral resistance was achieved by combining the proposed test method and the machine learning algorithm. This study can contribute to the synchronous detection of the mechanical state of ballast bed during tamping operation.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141953548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A hybrid methodology for the prediction of subway train-induced building vibrations based on the ground surface response","authors":"","doi":"10.1016/j.trgeo.2024.101330","DOIUrl":"10.1016/j.trgeo.2024.101330","url":null,"abstract":"<div><p>The numerical simulation and theoretical methods for the subway train-induced vibration of the shallow foundation buildings often suffer from high cost, unstable prediction accuracy, and lack of clarity of important parameters. Therefore, a hybrid prediction method based on the <em>Z</em>-vibration level at the ground surface was proposed to rapidly obtain the vibration characteristics of the shallow foundation building adjacent to the subway. The numerical simulation was first used to obtain the subway train-induced vibration of the shallow foundation building under different working conditions. Then, a hybrid model was established and retrained by combining the field measurement data of the soil and building vibration along the subway line. Finally, the prediction accuracy of the hybrid model with different numbers of measurement points as input layers was explored, and a case study was performed. The results show that the most noticeable effect on subway train-induced building vibration is the length of the building span among the shallow foundation building parameters. Three measurement points of the <em>Z</em>-vibration level at the ground surface are suggested as the training set data for the input layer of the hybrid model in consideration of computational efficiency and accuracy. The prediction accuracy of the hybrid model gradually increases as the number of data sets increases, and the fully trained hybrid model performs more stable across the frequency range compared to the traditional model, with the majority of its predictions in the 90% confidence interval, which provides the possibility of simplifying the analysis and fast prediction of subway train-induced building vibration.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the collapse susceptibility of loess using machine learning","authors":"","doi":"10.1016/j.trgeo.2024.101327","DOIUrl":"10.1016/j.trgeo.2024.101327","url":null,"abstract":"<div><p>Evaluating collapse susceptibility of loess is essential for the construction of transportation lines in loess regions as it provides guidance for ground treatment. For the existing methods, a large number of boreholes need to be drilled along transportation lines to collect intact samples for laboratory tests, which make them very time and cost-consuming. In this study, loess’s collapse susceptibility is evaluated using Multi Expression Programming (MEP) and Back-Propagation Neural Network (BPNN). According to analysis of wetting-induced loess collapse, the gravimetric water content at the initial state (<span><math><msub><mi>w</mi><mn>0</mn></msub></math></span>), net vertical stress (<span><math><mrow><mi>σ</mi><mo>-</mo><msub><mi>u</mi><mi>a</mi></msub></mrow></math></span>), void ratio at the initial state (<span><math><msub><mi>e</mi><mn>0</mn></msub></math></span>), void ratio at the liquid limit state (<span><math><msub><mi>e</mi><mi>L</mi></msub></math></span>), and plastic index (<span><math><msub><mi>I</mi><mi>p</mi></msub></math></span>) are chosen as input variables. A comprehensive database incorporating 200 oedometrically soaking tests is established to train and test the two algorithms. The collapse potentials of loess are well predicted using MEP and BPNN, as demonstrated by high values of coefficient of determination (<span><math><mrow><mspace></mspace><msup><mrow><mi>R</mi></mrow><mn>2</mn></msup><mo>&gt;</mo><mn>0.88</mn></mrow></math></span>) and small values of mean absolute error <span><math><mrow><mo>(</mo><mi>M</mi><mi>A</mi><mi>E</mi><mo>&lt;</mo><mn>0.008</mn><mo>)</mo></mrow></math></span> and root mean squared error <span><math><mrow><mo>(</mo><mi>R</mi><mi>M</mi><mi>S</mi><mi>E</mi><mo>&lt;</mo><mn>0.012</mn><mo>)</mo></mrow></math></span>. Following ASTM D5333-03 <span><span>[5]</span></span>, the degree of loess collapse is classified with accuracies of 98 % and 90 % for MEP and BNPP respectively. Furthermore, sensitivity analysis shows the contribution of each variable to the prediction of collapse potential follows the order of <span><math><mrow><msub><mi>e</mi><mn>0</mn></msub><mo>&gt;</mo><msub><mi>e</mi><mi>L</mi></msub><mo>&gt;</mo><msub><mi>I</mi><mi>p</mi></msub><mo>&gt;</mo><mi>σ</mi><mo>-</mo><msub><mi>u</mi><mi>a</mi></msub><mo>&gt;</mo><msub><mi>w</mi><mn>0</mn></msub></mrow></math></span>. The machine learning is expected to assist the code of practice ASTM D5333-03 <span><span>[5]</span></span> in achieving an efficient site-investigation of collapsible loess for the construction of transportation lines.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shear behaviors of expansive soils over a wide confining pressures range and their impacts on strength parameters","authors":"","doi":"10.1016/j.trgeo.2024.101328","DOIUrl":"10.1016/j.trgeo.2024.101328","url":null,"abstract":"<div><p>Understanding the shear behaviors of expansive soils under a wide range of confining pressures <em>σ</em>₃ is crucial for effectively managing their shallow hazards, especially at low <em>σ</em>₃ values. The shear behaviors of expansive soils under the low <em>σ</em>₃ values exhibit significant differences with those under the high <em>σ</em>₃ values, which have been inadequately addressed in existing research. This paper investigated the shear behaviors of two expansive soils across a wide range of <em>σ</em>₃ values (i.e., 15–400 kPa) through consolidated undrained triaxial tests. The results showed a significant nonlinear relationship between the shear strength and <em>σ</em>₃, particularly at the low <em>σ</em>₃ values. The nonlinearity of shear strength versus <em>σ</em>₃ in shallow expansive soils was described by a modified power function. As <em>σ</em>₃ decreased, both the brittleness index <em>λ</em> and curvature <em>κ</em> increased nonlinearly. Comparisons between the tangent method, based on the modified power function, and the <em>K</em>_f method, based on the Mohr-Coulomb criterion, suggested that neglecting the nonlinearity of shear strength versus <em>σ</em>₃ led to overestimations of the cohesion and underestimations of the internal friction angle at low <em>σ</em>₃ values, and the reverse trend was observed at high <em>σ</em>₃ values. The magnitude of these deviations depended on both the shear strength nonlinearity and the selected <em>σ</em>₃ values. The findings presented herein are helpful for the mitigation of shallow hazards in roadbeds, slopes, and foundation engineering associated with expansive soils.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-linear critical speed in high-speed ballasted railways with ground reinforcement","authors":"","doi":"10.1016/j.trgeo.2024.101325","DOIUrl":"10.1016/j.trgeo.2024.101325","url":null,"abstract":"<div><p>When constructing or upgrading high-speed railway lines on soft soils, reinforcing the soil foundation becomes crucial. This not only involves small track displacements but also increases the critical speed, thereby ensuring safe and efficient regular operations. Nevertheless, existing studies on the critical speed phenomenon in high-speed railway tracks with ground reinforcement are limited, and they all assume a linear elastic behavior for both the soils and reinforcement materials. The main novelty of this research is that it presents the first study on the effect of non-linear soil behavior on the critical speed of high-speed railway ballasted tracks with soil reinforcement and introduces a novel simplified approach based on an equivalent homogeneous soil layer by replacing the soil layer containing inclusions/columns. To accomplish this, a full 3D non-linear numerical model was developed and experimentally validated. The findings from a detailed and comprehensive parametric analysis demonstrate a significant influence of non-linear behavior on the critical speed, resulting in reductions of up to 30% compared to the linear elastic scenario. Furthermore, it is found that the soil-reinforcement stiffness contrast, the area replacement ratio, and the plasticity index of the soil foundation play a crucial role in the critical speed. Other aspects such as the installation pattern and the thickness of soft soil have a relatively lower impact on the critical speed.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214391224001466/pdfft?md5=f53b74893e2253ba1fdfcf376e49eeaf&pid=1-s2.0-S2214391224001466-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930761","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}

{"title":"An approach for strength development assessment of cement-stabilized soils with various sand and fine contents","authors":"","doi":"10.1016/j.trgeo.2024.101323","DOIUrl":"10.1016/j.trgeo.2024.101323","url":null,"abstract":"<div><p>Cement stabilization is a well-established ground improvement technique. However, there have been limited investigations aimed at the effect of heterogeneous soil types with varying amounts of coarse-grained (sand) and fine-grained (silt and clay) substances, on the strength enhancement of cement-stabilized soils. In this cement stabilization research study, sand (S) and clayey silt (F) were mixed together to have a variety between coarse- and fine-grained fractions at 100, 75, 50, 25, and 0 % by dry weight, designated as the ratio of S:F=100:0, 75:25, 50:50, 25:75, and 0:100, respectively. The water content was prepared at the range of 1.25–2.50 optimal water content to simulate field applications. The strength enhancement of cement-stabilized soils was influenced by the fine content, water content, and cement content. The soil–water to cement ratio (s-w/c) was effectively incorporate the impact of both water and cement contents on the strength enhancement, for a given a specific fine content. The generalized correlation between unconfined compressive strength, <em>q_u</em> and <em>s-w/c</em> could be represented as a power function: <em>q_u</em> = M/(<em>s-w/c</em>)^N. In this equation, M and N are constants that are primarily influenced by the fine content. The shear strength ratio versus fine content chart was proposed as a means to assess the effect of fine content on the strength of cement-stabilized soil with varying <em>s-w/c</em>. A stepwise approach for assessing the strength enhancement of cement stabilization in soil based on physical characteristics (i.e., plasticity index and fine content) was proposed and validated. The robustness of the proposed approach was realized by the low mean absolute percent error, (MAPE&lt;7.0 %) and high coefficient of determination (R² &gt; 0.95) for measured and predicted strengths comparison. This technique serves as a valuable tool for mix design, specifically in relation to clay mineral and fine content. It supports in making engineering decision regarding the appropriate amount of water and cement needed to achieve strength requirements throughout the requisite curing period, while minimizing the number of repetitions needed.</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical, mineralogical and geotechnical properties of volcanic ash of Tajogaite (La Palma, Canary Islands, Spain)","authors":"","doi":"10.1016/j.trgeo.2024.101326","DOIUrl":"10.1016/j.trgeo.2024.101326","url":null,"abstract":"<div><p>Volcanic eruption at La Palma island (Tajogaite, 2021) has produced tons of volcanic ash as natural sediments spread all around the island covering existing crops, roads, embankments, buildings, etc., by that way producing damage to environment. For the rehabilitation and reconstruction of island, and its application to adjacent areas, it is practical and economical to employ these volcanic ashes as construction material being encountered in abundant volume, and by that way could be considered as a resource material instead as a waste material, reducing necessary volume of landfills for its deposition. This paper defines the investigation of chemical, mineralogical and geotechnical properties of these deposited materials for its possible reuse by that way providing solution for its recovery. These young volcanic ashes are studied in its fresh natural state, prior to consolidation and cementation has taken place for its chemical, mineralogical and geotechnical characterization. Volcanic ash of Tajogaite is of a poorly graded sandy nature having difficulties for its compaction, having low improvement of relative density by the application of standard compaction methods. Mineralogy analysis indicates it is rich in silica, iron, calcium and alumina oxide, although being necessary the addition of mineral additives for its alkali-activation. Geotechnical characteristics of different samples vary depending on the sampling site, being resistance parameters determined by direct shear test (friction angle 30° to 34°) and deformational properties defined by one-dimensional consolidation test considered low values as of loose sand materials (deformation modulus range from 20 to 40 MPa).</p></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2214391224001478/pdfft?md5=f1ebe83bebbc8425dffb2a0c199e3085&pid=1-s2.0-S2214391224001478-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930697","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}