Transportation Geotechnics最新文献_第3页

Research on dynamic response characteristics of red clay low embankment with different road structures under vehicle load 不同路面结构的红粘土低路堤在车辆荷载作用下的动态响应特性研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-11-01 DOI: 10.1016/j.trgeo.2024.101427

Jinhong Li , Hongyuan Fu , Xiang Qiu , Yong Wu , Jingchen Chen

During the operation period of a red clay low embankment, significant uneven settlement can occur due to vehicle loads, seriously threatening the smooth flow of roads and transportation safety. To better inform the design and filling of red clay low embankment road structures, this study combines model tests and numerical simulations to investigate the dynamic response characteristics of various pavement structures on red clay low embankments under vehicular loads. It examines how different moisture contents, embankment parameters, driving parameters, and pavement structures affect the vertical dynamic stress, acceleration, and deformation of red clay low embankments. The results show that the vertical dynamic stress and acceleration decrease rapidly along the depth and transverse width directions, and then slowly decrease. Increased vehicle loads and speeds lead to greater vertical dynamic stress and acceleration, whereas higher elastic modulus and embankment soil thickness result in lower values. Additionally, increasing water content intensifies the vertical acceleration response in red clay low embankments. The influence degree of different factors on the dynamic characteristics of red clay low embankment is: vehicle load > driving speed > embankment thickness > elastic modulus of embankment soil. The red clay low embankment under vehicular loading belongs to the deformation concentration area within 0 to 0.4 m from the top surface of the embankment. A comparative analysis of the dynamic characteristics of six common pavement structures for red clay low embankments shows that rutting-resistant pavement structures perform the best. The proposed new type of red clay low embankment upper pavement structure can effectively avoid the problem of base water damage caused by the capillary water rise of red clay.

红粘土低路堤在运行期间，由于车辆荷载的作用会产生明显的不均匀沉降，严重威胁道路的畅通和交通安全。为了更好地指导红粘土低路堤道路结构的设计和填筑，本研究结合模型试验和数值模拟，研究了红粘土低路堤上各种路面结构在车辆荷载作用下的动态响应特性。研究探讨了不同含水量、路堤参数、行车参数和路面结构如何影响红粘土低路堤的垂直动应力、加速度和变形。结果表明，垂直动应力和加速度沿深度和横向宽度方向迅速减小，然后缓慢减小。车辆荷载和速度增加会导致垂直动应力和加速度增大，而弹性模量和路堤土厚度增加则会导致数值减小。此外，含水量的增加会加剧红粘土低路堤的垂直加速度响应。不同因素对红粘土低路堤动态特性的影响程度分别为：车辆荷载；行驶速度；路堤厚度；路堤土的弹性模量。车辆荷载作用下的红粘土低路堤在距路堤顶面 0~0.4 m 范围内属于变形集中区。对六种常见的红粘土低路堤路面结构的动态特性进行比较分析表明，抗车辙路面结构的性能最好。所提出的新型红粘土低路堤上层路面结构可有效避免红粘土毛细水上升引起的基底水破坏问题。

{"title":"Research on dynamic response characteristics of red clay low embankment with different road structures under vehicle load","authors":"Jinhong Li , Hongyuan Fu , Xiang Qiu , Yong Wu , Jingchen Chen","doi":"10.1016/j.trgeo.2024.101427","DOIUrl":"10.1016/j.trgeo.2024.101427","url":null,"abstract":"<div><div>During the operation period of a red clay low embankment, significant uneven settlement can occur due to vehicle loads, seriously threatening the smooth flow of roads and transportation safety. To better inform the design and filling of red clay low embankment road structures, this study combines model tests and numerical simulations to investigate the dynamic response characteristics of various pavement structures on red clay low embankments under vehicular loads. It examines how different moisture contents, embankment parameters, driving parameters, and pavement structures affect the vertical dynamic stress, acceleration, and deformation of red clay low embankments. The results show that the vertical dynamic stress and acceleration decrease rapidly along the depth and transverse width directions, and then slowly decrease. Increased vehicle loads and speeds lead to greater vertical dynamic stress and acceleration, whereas higher elastic modulus and embankment soil thickness result in lower values. Additionally, increasing water content intensifies the vertical acceleration response in red clay low embankments. The influence degree of different factors on the dynamic characteristics of red clay low embankment is: vehicle load > driving speed > embankment thickness > elastic modulus of embankment soil. The red clay low embankment under vehicular loading belongs to the deformation concentration area within 0 to 0.4 m from the top surface of the embankment. A comparative analysis of the dynamic characteristics of six common pavement structures for red clay low embankments shows that rutting-resistant pavement structures perform the best. The proposed new type of red clay low embankment upper pavement structure can effectively avoid the problem of base water damage caused by the capillary water rise of red clay.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101427"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593399","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}

引用次数: 0

Stiffness evaluation of coarse unbound granular materials using large-scale repeated load triaxial test 利用大型重复加载三轴试验评估粗颗粒材料的刚度

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-11-01 DOI: 10.1016/j.trgeo.2024.101423

Lisa Tronhuus Hannasvik , Inge Hoff , Diego Maria Barbieri

This research investigates the effect of downscaling coarse unbound granular material (UGM) for characterization of the resilient modulus with large-scale repeated load triaxial testing. Four open-graded and two dense-graded materials are downscaled based on the particle size distribution curve and upper sieve size for subbase materials of crushed rock (CR) 22/125 mm and CR 0/125 mm as defined by the Norwegian road design regulation.

The results were evaluated using the K-θ model and Uzan’s model. The findings for CR 4/22 mm, CR 6/32 mm, CR 8/45 mm, and CR 11/63 mm indicate that downscaling of coarse open-graded UGMs could be applicable for characterization of the resilient modulus. The results for dense-graded UGMs CR 0/22 mm and CR 0/63 mm indicate that downscaling reduces the resilient modulus. Further research should include complementary gradings and rock types.

本研究调查了通过大规模重复加载三轴试验对粗颗粒材料（UGM）进行降级处理对表征回弹模量的影响。根据粒度分布曲线和挪威道路设计规定的碎石（CR）22/125 毫米和 CR 0/125 毫米路基材料的上筛粒度，对四种开级配材料和两种密级配材料进行了降级。对 CR 4/22 毫米、CR 6/32 毫米、CR 8/45 毫米和 CR 11/63 毫米的研究结果表明，粗粒式开放级配 UGM 的降级可用于表征回弹模量。CR 0/22 毫米和 CR 0/63 毫米密级配 UGM 的结果表明，降级会降低回弹模量。进一步的研究应包括补充级配和岩石类型。

引用次数: 0

Experimental and numerical investigation of seepage erosion in sandy cobbles under coupling hydraulic and dynamic load 水力和动力荷载耦合作用下砂质鹅卵石渗流侵蚀的实验和数值研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-11-01 DOI: 10.1016/j.trgeo.2024.101429

Jinyang Fu , Zhou Yang , Qianhui Sun , Yipeng Xie , Junsheng Yang

The internal structure of sandy cobbles strata is sensitive to disturbances in the urban underground environment, but the structural evolution process under coupling hydraulic and dynamic loads remains unexplored. This paper presents a detailed investigation into the migration patterns and mechanisms of fine particles in sandy cobbles induced by coupled hydraulic and dynamic loading. A sandy cobble specimen with a typical particle size distribution (PSD) was designed and tested using an apparatus that included a constant inlet water head control system and an eccentric-vibrator-based dynamic loading system. Based on physical modeling tests, a numerical model was constructed to reproduce the internal structural evolution under hydraulic and dynamic loading by calibrating the time history of local permeability. The test results indicate that the application of dynamic load can instantly disrupt the stable internal structure of sandy cobbles under static seepage, imparting kinetic energy to fine particles that detach from the skeleton structure and migrate along the seepage direction. Significant fine particle loss occurs near the seepage outlet, but due to energy loss during migration, fine particles far from the seepage outlet are recaptured by the skeleton pore throats and clogged again in the migration path. As the intensity of the dynamic loading increases, the migration path for fine particles becomes longer, and the amount and size of fine particles lost significantly increase. The changes in the internal structure of the soil are reflected in hydraulic parameters as a transient increase in local flow velocity, an increase in local pore water pressure due to clogging, and a decrease in the overall permeability coefficient with the loss of fine particles. These findings enrich the knowledge of internal erosion in urban underground environmentand will be meaningful for future geotechnical engineering design and analysis.

砂卵石地层的内部结构对城市地下环境的扰动非常敏感，但其在水力和动力荷载耦合作用下的结构演化过程仍有待探索。本文详细研究了水力和动力荷载耦合作用下砂质鹅卵石中细颗粒的迁移规律和机制。设计了一个具有典型粒度分布（PSD）的砂卵石试样，并使用包括恒定进水水头控制系统和基于偏心振动器的动态加载系统的设备进行了测试。在物理建模试验的基础上，通过校准局部渗透率的时间历程，构建了一个数值模型，以再现水力和动态加载下的内部结构演变。试验结果表明，在静态渗流条件下，施加动荷载会瞬间破坏砂质鹅卵石稳定的内部结构，将动能传递给细颗粒，使其脱离骨架结构并沿渗流方向迁移。细颗粒在渗流出口附近大量流失，但由于迁移过程中的能量损失，远离渗流出口的细颗粒会被骨架孔隙重新捕获，并再次堵塞在迁移路径上。随着动荷载强度的增加，细颗粒的迁移路径变长，损失的细颗粒数量和粒径也显著增加。土壤内部结构的变化反映在水力参数上，表现为局部流速的瞬时增加、堵塞导致的局部孔隙水压力的增加，以及随着细颗粒的流失，整体渗透系数的降低。这些发现丰富了人们对城市地下环境内部侵蚀的认识，对未来岩土工程设计和分析具有重要意义。

{"title":"Experimental and numerical investigation of seepage erosion in sandy cobbles under coupling hydraulic and dynamic load","authors":"Jinyang Fu , Zhou Yang , Qianhui Sun , Yipeng Xie , Junsheng Yang","doi":"10.1016/j.trgeo.2024.101429","DOIUrl":"10.1016/j.trgeo.2024.101429","url":null,"abstract":"<div><div>The internal structure of sandy cobbles strata is sensitive to disturbances in the urban underground environment, but the structural evolution process under coupling hydraulic and dynamic loads remains unexplored. This paper presents a detailed investigation into the migration patterns and mechanisms of fine particles in sandy cobbles induced by coupled hydraulic and dynamic loading. A sandy cobble specimen with a typical particle size distribution (PSD) was designed and tested using an apparatus that included a constant inlet water head control system and an eccentric-vibrator-based dynamic loading system. Based on physical modeling tests, a numerical model was constructed to reproduce the internal structural evolution under hydraulic and dynamic loading by calibrating the time history of local permeability. The test results indicate that the application of dynamic load can instantly disrupt the stable internal structure of sandy cobbles under static seepage, imparting kinetic energy to fine particles that detach from the skeleton structure and migrate along the seepage direction. Significant fine particle loss occurs near the seepage outlet, but due to energy loss during migration, fine particles far from the seepage outlet are recaptured by the skeleton pore throats and clogged again in the migration path. As the intensity of the dynamic loading increases, the migration path for fine particles becomes longer, and the amount and size of fine particles lost significantly increase. The changes in the internal structure of the soil are reflected in hydraulic parameters as a transient increase in local flow velocity, an increase in local pore water pressure due to clogging, and a decrease in the overall permeability coefficient with the loss of fine particles. These findings enrich the knowledge of internal erosion in urban underground environmentand will be meaningful for future geotechnical engineering design and analysis.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101429"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578171","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}

引用次数: 0

Designing ballastless high-speed railways in frozen regions: A dynamic analysis using three-dimensional numerical modelling 在冰冻地区设计无砟高速铁路：利用三维数值建模进行动态分析

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-11-01 DOI: 10.1016/j.trgeo.2024.101435

Shuang Tian , Liang Tang , Xianzhang Ling , Shi Liu , Ting Li

Many high-speed railways (HSRs) have been constructed in the frozen regions of China, with additional lines expected to be developed in the future. However, research into the dynamic response of embankments in these regions under moving train loads has been limited, particularly in view of potentially increased train speeds. Therefore, this study developed an indirect thermal–dynamic coupled three-dimensional finite-element model to investigate the dynamic responses of railway subgrades induced by high-speed trains in frozen regions. The study examined dynamic responses in relation to underlying layer stiffness, frost depth, and train speed. Dynamic amplification factors for train speed and frost depth were derived from statistical analysis of simulation results. A potential method was proposed to predict the long-term track performance of HSRs in frozen regions under conditions of higher train speeds. The study suggests practical recommendations, providing essential guidance to railway engineers in devising optimal strategies for railway design in frozen regions.

中国的冰冻地区已建成多条高速铁路（HSR），预计未来还将开发更多线路。然而，对这些地区的路堤在动车荷载作用下的动态响应研究还很有限，特别是考虑到列车速度可能会提高。因此，本研究开发了一个间接热动力耦合三维有限元模型，以研究高速列车在冰冻地区引起的铁路路基动态响应。研究考察了与底层刚度、结霜深度和列车速度相关的动态响应。通过对模拟结果进行统计分析，得出了列车速度和霜冻深度的动态放大系数。研究提出了一种潜在的方法，用于预测列车速度较高条件下高铁在冰冻地区的长期轨道性能。研究提出了一些实用建议，为铁路工程师制定冰冻地区铁路设计的最佳策略提供了重要指导。

{"title":"Designing ballastless high-speed railways in frozen regions: A dynamic analysis using three-dimensional numerical modelling","authors":"Shuang Tian , Liang Tang , Xianzhang Ling , Shi Liu , Ting Li","doi":"10.1016/j.trgeo.2024.101435","DOIUrl":"10.1016/j.trgeo.2024.101435","url":null,"abstract":"<div><div>Many high-speed railways (HSRs) have been constructed in the frozen regions of China, with additional lines expected to be developed in the future. However, research into the dynamic response of embankments in these regions under moving train loads has been limited, particularly in view of potentially increased train speeds. Therefore, this study developed an indirect thermal–dynamic coupled three-dimensional finite-element model to investigate the dynamic responses of railway subgrades induced by high-speed trains in frozen regions. The study examined dynamic responses in relation to underlying layer stiffness, frost depth, and train speed. Dynamic amplification factors for train speed and frost depth were derived from statistical analysis of simulation results. A potential method was proposed to predict the long-term track performance of HSRs in frozen regions under conditions of higher train speeds. The study suggests practical recommendations, providing essential guidance to railway engineers in devising optimal strategies for railway design in frozen regions.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101435"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652756","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}

引用次数: 0

Mechanical response of buried water pipes to traffic loading before and after extreme cold waves 埋地水管在极端寒潮前后对交通负荷的机械响应

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-11-01 DOI: 10.1016/j.trgeo.2024.101418

Qunfang Hu , Olawale Ayinde , Wen Liu

In recent years, the escalating frequency and intensity of extreme weather events like cold waves have heightened concerns regarding their impact on buried water pipelines, posing notable challenges to urban safety. These pipelines are particularly vulnerable to damage from the extreme low temperatures induced by cold waves, which can lead to significant system failures. This paper investigates the mechanical response of buried water pipelines to traffic loading before and after a cold wave using the Finite Element Method (FEM). Initially, a 3D numerical model was created to simulate the temperature distribution in the soil and buried pipe, utilizing field monitoring data gathered during a cold wave event at Shanghai city of Eastern China. Subsequently, a mechanical analysis of the soil-pipe model was conducted, employing the validated soil and pipe temperature field as predefined fields. The effects of temperature change rate, traffic load type, load position, and burial depth on the pipeline behavior are discussed in detail. The results demonstrated that cold waves significantly impact pipeline stress, an effect that is intensified by increased traffic loads. The peak Mises stress increased by up to 21 % for the 1.0 MPa load, underscoring the role of cold waves in amplifying pipeline stress. Moreover, while cold waves increase pipeline stress and vertical displacement, accelerating the rate of temperature change induced by the cold wave reduces the stress. Traffic load exerts the most significant impact at the bell and spigot joints, with effects remaining consistent regardless of joint position. Shallow-buried pipelines experience more pronounced stress changes in the presence of cold waves and traffic load, with stress increasing by 66.8 % at a depth of 1.5 m. This study demonstrates that the bell and spigot joints of shallow-buried pipes are highly susceptible to cold wave effects, especially under traffic loading, necessitating special attention to this potential failure location during such conditions.

近年来，寒潮等极端天气事件发生的频率和强度不断上升，加剧了人们对其对埋地输水管道影响的担忧，给城市安全带来了显著挑战。这些管道尤其容易受到寒潮引起的极端低温的破坏，从而导致严重的系统故障。本文采用有限元法 (FEM) 研究了寒潮前后埋地输水管道对交通荷载的机械响应。首先，利用在中国东部上海市寒潮期间收集的现场监测数据，创建了一个三维数值模型，以模拟土壤和埋地管道中的温度分布。随后，将验证的土壤和管道温度场作为预定义场，对土壤-管道模型进行了力学分析。详细讨论了温度变化率、交通荷载类型、荷载位置和埋深对管道行为的影响。结果表明，寒潮会对管道应力产生显著影响，而交通荷载的增加会加剧这种影响。在 1.0 兆帕载荷下，米塞斯应力峰值增加了 21%，这说明了冷波在放大管道应力方面的作用。此外，虽然寒潮会增加管道应力和垂直位移，但加快寒潮引起的温度变化速度会降低应力。交通荷载对喇叭口和拉钉接头上的影响最大，无论接头上的位置如何，影响都是一致的。这项研究表明，浅埋管道的喇叭口和拉钉节极易受到寒潮的影响，尤其是在交通荷载下，因此在这种情况下有必要特别关注这一潜在的失效位置。

{"title":"Mechanical response of buried water pipes to traffic loading before and after extreme cold waves","authors":"Qunfang Hu , Olawale Ayinde , Wen Liu","doi":"10.1016/j.trgeo.2024.101418","DOIUrl":"10.1016/j.trgeo.2024.101418","url":null,"abstract":"<div><div>In recent years, the escalating frequency and intensity of extreme weather events like cold waves have heightened concerns regarding their impact on buried water pipelines, posing notable challenges to urban safety. These pipelines are particularly vulnerable to damage from the extreme low temperatures induced by cold waves, which can lead to significant system failures. This paper investigates the mechanical response of buried water pipelines to traffic loading before and after a cold wave using the Finite Element Method (FEM). Initially, a 3D numerical model was created to simulate the temperature distribution in the soil and buried pipe, utilizing field monitoring data gathered during a cold wave event at Shanghai city of Eastern China. Subsequently, a mechanical analysis of the soil-pipe model was conducted, employing the validated soil and pipe temperature field as predefined fields. The effects of temperature change rate, traffic load type, load position, and burial depth on the pipeline behavior are discussed in detail. The results demonstrated that cold waves significantly impact pipeline stress, an effect that is intensified by increased traffic loads. The peak Mises stress increased by up to 21 % for the 1.0 MPa load, underscoring the role of cold waves in amplifying pipeline stress. Moreover, while cold waves increase pipeline stress and vertical displacement, accelerating the rate of temperature change induced by the cold wave reduces the stress. Traffic load exerts the most significant impact at the bell and spigot joints, with effects remaining consistent regardless of joint position. Shallow-buried pipelines experience more pronounced stress changes in the presence of cold waves and traffic load, with stress increasing by 66.8 % at a depth of 1.5 m. This study demonstrates that the bell and spigot joints of shallow-buried pipes are highly susceptible to cold wave effects, especially under traffic loading, necessitating special attention to this potential failure location during such conditions.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101418"},"PeriodicalIF":4.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554139","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}

引用次数: 0

Developing a real-time compaction quality assessment methodology for subgrade based on semi-supervised co-training 开发基于半监督联合训练的路基压实质量实时评估方法

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-10-22 DOI: 10.1016/j.trgeo.2024.101412

Xuefei Wang , Yingwei Su , Jiale Li , Jianmin Zhang , Guowei Ma

The current intelligent methodologies for real-time evaluation of subgrade compaction quality predominantly rely on supervised machine learning algorithms. However, the scarcity of sand cone test significantly impedes model performance, thereby severely limiting the applicability of intelligent subgrade compaction. This paper proposes a semi-supervised co-training algorithm for real-time evaluation of subgrade compactness during the construction procedure, leveraging unlabeled data to enhance the model performance. Based on the compaction datasets from various subgrade scenarios, the proposed PSO-XGB-Co-training KNN-PLS (PSO-XGB-CoKP) algorithm is utilized to train the unlabeled data, boasting a 20.4% reduction in Mean Squared Error (MSE). The semi-supervised co-training algorithm is modified by employing different regressors as co-trained sub-models and increasing the number of regressors. The model is optimized by levering the accuracy and computational cost, and an optimal data augmentation volume is recommended through the sensitivity study. This study provides an alternative approach for leveraging unbalanced and small-sample datasets to develop a reliable intelligent methodology for evaluating subgrade compaction quality in engineering practice.

目前用于实时评估路基压实质量的智能方法主要依赖于有监督的机器学习算法。然而，砂锥试验的稀缺性极大地阻碍了模型性能的发挥，从而严重限制了智能路基压实的适用性。本文提出了一种半监督协同训练算法，用于在施工过程中实时评估路基压实度，利用未标记数据提高模型性能。基于不同路基场景下的压实数据集，本文提出了 PSO-XGB-Co-training KNN-PLS 算法（PSO-XGB-CoKP）来训练非标记数据，其平均平方误差（MSE）降低了 20.4%。通过采用不同的回归因子作为协同训练子模型并增加回归因子的数量，对半监督协同训练算法进行了修改。通过对精确度和计算成本的杠杆作用对模型进行了优化，并通过灵敏度研究推荐了最佳数据增量。这项研究为利用不平衡和小样本数据集开发可靠的智能方法提供了另一种方法，用于评估工程实践中的路基压实质量。

{"title":"Developing a real-time compaction quality assessment methodology for subgrade based on semi-supervised co-training","authors":"Xuefei Wang , Yingwei Su , Jiale Li , Jianmin Zhang , Guowei Ma","doi":"10.1016/j.trgeo.2024.101412","DOIUrl":"10.1016/j.trgeo.2024.101412","url":null,"abstract":"<div><div>The current intelligent methodologies for real-time evaluation of subgrade compaction quality predominantly rely on supervised machine learning algorithms. However, the scarcity of sand cone test significantly impedes model performance, thereby severely limiting the applicability of intelligent subgrade compaction. This paper proposes a semi-supervised co-training algorithm for real-time evaluation of subgrade compactness during the construction procedure, leveraging unlabeled data to enhance the model performance. Based on the compaction datasets from various subgrade scenarios, the proposed PSO-XGB-Co-training KNN-PLS (PSO-XGB-CoKP) algorithm is utilized to train the unlabeled data, boasting a 20.4% reduction in Mean Squared Error (MSE). The semi-supervised co-training algorithm is modified by employing different regressors as co-trained sub-models and increasing the number of regressors. The model is optimized by levering the accuracy and computational cost, and an optimal data augmentation volume is recommended through the sensitivity study. This study provides an alternative approach for leveraging unbalanced and small-sample datasets to develop a reliable intelligent methodology for evaluating subgrade compaction quality in engineering practice.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101412"},"PeriodicalIF":4.9,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538693","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}

引用次数: 0

Super-large diameter slurry shield tunnel encountering boulder formation: Detection, treatment and data analysis 超大直径泥浆盾构隧道遭遇巨石层：检测、处理和数据分析

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-10-18 DOI: 10.1016/j.trgeo.2024.101408

Wei-Hong Yang , Dong Su , Xing-Tao Lin , Zhi-Jia Lv , Zhan-Hu Yao , Hui Li , Ya-Zhou Zhang , Xiang-Sheng Chen

Boulders pose substantial challenges in coastal urban tunnel engineering. This study, for the first time, utilizes extensive closely spaced borehole data from 3486 drilling points obtained during actual tunnelling through boulder strata to evaluate the effectiveness of microtremor detection, analyze variations in operational parameters, and assess the efficiency of blasting treatment. Additionally, leveraging borehole data, a 3D reconstruction of the soil-boulder-bedrock stratum was developed, and the stratum content ratio at the excavation face was derived. A multivariate linear regression model was established to explore the relationship between boulder geology and construction parameters. The results demonstrated that microtremor surveys effectively identified boulder distributions by analyzing horizontal-to-vertical spectral ratio curves and differences in surface wave phase velocity. Field drilling confirmed the high accuracy of microtremor predictions, particularly in areas with dense or thick boulder layers. Post-blasting secondary drilling revealed boulder fragments smaller than 30 cm, meeting the operational requirements for shield cutter and crusher systems. The presence of boulders was found to increase thrust, torque, and overturning moments, as well as cause abnormal cutter wear. Blasting significantly reduced the standard deviation of operational data, demonstrating its effectiveness in stabilizing tunnelling performance. Regression analysis showed a strong correlation between geological conditions and tunnelling parameters, with results indicating that blasting operations effectively mitigate the adverse impacts of boulders on shield tunnelling performance. This study aims to provide valuable insights and references for future engineering projects encountering similar complex geological conditions.

巨石给沿海城市隧道工程带来了巨大挑战。本研究首次利用实际隧道穿越巨石地层过程中获得的 3486 个钻孔点的大量密间距钻孔数据，评估了微震探测的有效性，分析了操作参数的变化，并评估了爆破处理的效率。此外，利用钻孔数据，开发了土壤-巨石-岩石地层的三维重建，并得出了开挖面的地层含量比。建立了多元线性回归模型，以探讨巨石地质与施工参数之间的关系。结果表明，通过分析水平-垂直频谱比曲线和表面波相位速度差异，微震波勘测可有效识别巨石分布。实地钻探证实了微震波预测的高准确性，尤其是在巨石层密集或厚的区域。爆破后的二次钻探发现了小于 30 厘米的巨石碎片，符合盾构刀盘和破碎机系统的操作要求。研究发现，巨石的存在会增加推力、扭矩和倾覆力矩，并导致刀盘异常磨损。爆破大大降低了运行数据的标准偏差，证明了其在稳定隧道性能方面的有效性。回归分析表明，地质条件与隧道参数之间具有很强的相关性，结果表明爆破作业可有效减轻巨石对盾构隧道性能的不利影响。本研究旨在为今后遇到类似复杂地质条件的工程项目提供有价值的见解和参考。

{"title":"Super-large diameter slurry shield tunnel encountering boulder formation: Detection, treatment and data analysis","authors":"Wei-Hong Yang , Dong Su , Xing-Tao Lin , Zhi-Jia Lv , Zhan-Hu Yao , Hui Li , Ya-Zhou Zhang , Xiang-Sheng Chen","doi":"10.1016/j.trgeo.2024.101408","DOIUrl":"10.1016/j.trgeo.2024.101408","url":null,"abstract":"<div><div>Boulders pose substantial challenges in coastal urban tunnel engineering. This study, for the first time, utilizes extensive closely spaced borehole data from 3486 drilling points obtained during actual tunnelling through boulder strata to evaluate the effectiveness of microtremor detection, analyze variations in operational parameters, and assess the efficiency of blasting treatment. Additionally, leveraging borehole data, a 3D reconstruction of the soil-boulder-bedrock stratum was developed, and the stratum content ratio at the excavation face was derived. A multivariate linear regression model was established to explore the relationship between boulder geology and construction parameters. The results demonstrated that microtremor surveys effectively identified boulder distributions by analyzing horizontal-to-vertical spectral ratio curves and differences in surface wave phase velocity. Field drilling confirmed the high accuracy of microtremor predictions, particularly in areas with dense or thick boulder layers. Post-blasting secondary drilling revealed boulder fragments smaller than 30 cm, meeting the operational requirements for shield cutter and crusher systems. The presence of boulders was found to increase thrust, torque, and overturning moments, as well as cause abnormal cutter wear. Blasting significantly reduced the standard deviation of operational data, demonstrating its effectiveness in stabilizing tunnelling performance. Regression analysis showed a strong correlation between geological conditions and tunnelling parameters, with results indicating that blasting operations effectively mitigate the adverse impacts of boulders on shield tunnelling performance. This study aims to provide valuable insights and references for future engineering projects encountering similar complex geological conditions.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101408"},"PeriodicalIF":4.9,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532860","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}

引用次数: 0

Performance evaluation of high early strength micro-expansion geopolymer grout potentially used for sustainable road infrastructure 可用于可持续道路基础设施的高早期强度微膨胀土工聚合物灌浆料性能评估

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-10-17 DOI: 10.1016/j.trgeo.2024.101400

Junhui Zhang , Hualei Wang , Ahmed M. Awed , Jianwei Xie , Fan Gu

This study aimed to develop a high early strength micro-expansion geopolymer grout material derived from recycled concrete and ground granulated blast-furnace slag (GGBS), which can be used to fill the subgrade voids and strengthen weak subgrade. A series of grout materials with varying proportions of recycled concrete were prepared, and their setting time, flowability, and strength characteristics were evaluated. The results indicated that the grout material containing 50 % recycled concrete had a final setting time of 29 min, a flow time of 15.2 s, and a 7-day compressive strength of 40.6 MPa, all of which met the requirements for subgrade grout materials. To further enhance the performance of the grout, the additives including 2 % calcium chloride (CaCl₂), 5 % magnesium oxide (MgO), and 5 % united expansive agent (UEA) were used. Results showed that the samples containing 50 % recycled concrete and 2 % CaCl₂ exhibited a 26.5 % increase in strength after 100 min of curing, while MgO and UEA reduced shrinkage by 112.5 % and 90.0 %, respectively. Additionally, microstructural analysis using SEM and XRD provided valuable insights into the complex interactions between components and their effects on material integrity. The results demonstrated that the use of CaCl₂ accelerated the hydration reaction, enhancing early strength, while the expansion agents MgO and UEA mitigated shrinkage and achieved micro-expansion at low concrete content. This study addresses environmental concerns by incorporating recycled materials, positioning the developed geopolymer grout as a sustainable, high-performance alternative in road construction. Integrating waste-derived components and innovative additives represents a significant step towards advancing sustainable practices in infrastructure development.

本研究旨在开发一种源自再生混凝土和磨细高炉矿渣（GGBS）的高早强微膨胀土工聚合物灌浆材料，用于填充路基空隙和加固软弱路基。研究人员制备了一系列含有不同比例再生混凝土的灌浆材料，并对其凝结时间、流动性和强度特性进行了评估。结果表明，含有 50% 再生混凝土的灌浆材料的终凝时间为 29 分钟，流动时间为 15.2 秒，7 天抗压强度为 40.6 兆帕，均符合路基灌浆材料的要求。为了进一步提高灌浆料的性能，还使用了添加剂，包括 2 % 的氯化钙（CaCl2）、5 % 的氧化镁（MgO）和 5 % 的联合膨胀剂（UEA）。结果表明，含有 50 % 再生混凝土和 2 % CaCl2 的样品在 100 分钟养护后强度提高了 26.5%，而氧化镁和 UEA 则分别减少了 112.5 % 和 90.0 % 的收缩。此外，利用扫描电子显微镜和 XRD 进行的微观结构分析为了解成分之间复杂的相互作用及其对材料完整性的影响提供了宝贵的见解。结果表明，CaCl2 的使用加速了水化反应，提高了早期强度，而膨胀剂 MgO 和 UEA 则减轻了收缩，并在混凝土含量较低时实现了微膨胀。这项研究通过采用回收材料解决了环境问题，将所开发的土工聚合物灌浆料定位为道路建设中一种可持续的高性能替代材料。将废物衍生成分与创新添加剂相结合，是在基础设施建设中推进可持续发展实践的重要一步。

{"title":"Performance evaluation of high early strength micro-expansion geopolymer grout potentially used for sustainable road infrastructure","authors":"Junhui Zhang , Hualei Wang , Ahmed M. Awed , Jianwei Xie , Fan Gu","doi":"10.1016/j.trgeo.2024.101400","DOIUrl":"10.1016/j.trgeo.2024.101400","url":null,"abstract":"<div><div>This study aimed to develop a high early strength micro-expansion geopolymer grout material derived from recycled concrete and ground granulated blast-furnace slag (GGBS), which can be used to fill the subgrade voids and strengthen weak subgrade. A series of grout materials with varying proportions of recycled concrete were prepared, and their setting time, flowability, and strength characteristics were evaluated. The results indicated that the grout material containing 50 % recycled concrete had a final setting time of 29 min, a flow time of 15.2 s, and a 7-day compressive strength of 40.6 MPa, all of which met the requirements for subgrade grout materials. To further enhance the performance of the grout, the additives including 2 % calcium chloride (CaCl<sub>2</sub>), 5 % magnesium oxide (MgO), and 5 % united expansive agent (UEA) were used. Results showed that the samples containing 50 % recycled concrete and 2 % CaCl<sub>2</sub> exhibited a 26.5 % increase in strength after 100 min of curing, while MgO and UEA reduced shrinkage by 112.5 % and 90.0 %, respectively. Additionally, microstructural analysis using SEM and XRD provided valuable insights into the complex interactions between components and their effects on material integrity. The results demonstrated that the use of CaCl<sub>2</sub> accelerated the hydration reaction, enhancing early strength, while the expansion agents MgO and UEA mitigated shrinkage and achieved micro-expansion at low concrete content. This study addresses environmental concerns by incorporating recycled materials, positioning the developed geopolymer grout as a sustainable, high-performance alternative in road construction. Integrating waste-derived components and innovative additives represents a significant step towards advancing sustainable practices in infrastructure development.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101400"},"PeriodicalIF":4.9,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532859","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}

引用次数: 0

Fiber-reinforced shotcrete lining for stabilizing rock blocks around underground cavities 用于稳定地下空洞周围岩块的纤维增强喷射混凝土衬里

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-10-16 DOI: 10.1016/j.trgeo.2024.101407

Pierpaolo Oreste , Claudio Oggeri , Giovanni Spagnoli

Fiber-reinforced shotcrete is a high-performance material that presents some special characteristics, which can provide some suitable applications in the excavation of underground cavities. The presence of fibers induces an increase in the tensile strength, flexural strength and shear strength in the concrete, as well as allowing a ductile rather than brittle type of behavior. It can be used to create a lining of the underground cavity that allows the stabilization of rock blocks that show a tendency to slip or fall (from the side walls or from the crown area, respectively). In this work, some full-scale tests on the fiber-reinforced shotcrete lining are presented. From these tests, it was possible to measure the behavior of this material when it is loaded locally: it is the same type of action produced by the rock block when it is held back from falling or slipping. The results obtained have allowed to characterize this type of material from a mechanical point of view. A subsequent detailed analysis of the stability of rock blocks surrounding an underground cavity permitted to determine the static stabilizing contribution offered by the fiber-reinforced shotcrete lining, leading to the definition of the minimum thickness required, in relation to the type of block that is present (shape and size). It was possible to predict how a lining thickness of about 3.5 cm is able to stabilize (just 15 min after its spraying) rock blocks with an exposed surface area of up to 10 m² and a distance of the internal vertex from the border of the cavity of up to 3 m.

纤维增强喷射混凝土是一种高性能材料，具有一些特殊的特性，可以在挖掘地下空洞时提供一些合适的应用。纤维的存在可提高混凝土的抗拉强度、抗弯强度和抗剪强度，并使其具有韧性而非脆性。它可用于创建地下空腔的衬里，从而稳定有滑落或坠落倾向的岩块（分别从侧壁或顶部）。在这项工作中，对纤维增强喷射混凝土衬里进行了一些全面的测试。通过这些试验，我们可以测量这种材料在局部受力时的行为：这与岩块在受阻时产生的作用类型相同，即防止岩块掉落或滑落。所获得的结果有助于从机械角度分析这种材料的特性。随后对地下空洞周围岩块的稳定性进行了详细分析，从而确定了纤维增强喷射混凝土衬里的静态稳定作用，并根据岩块的类型（形状和大小）确定了所需的最小厚度。我们可以预测，厚度约为 3.5 厘米的内衬如何能够稳定（喷射后 15 分钟内）暴露表面积达 10 平方米、内部顶点距空腔边界距离达 3 米的岩块。

{"title":"Fiber-reinforced shotcrete lining for stabilizing rock blocks around underground cavities","authors":"Pierpaolo Oreste , Claudio Oggeri , Giovanni Spagnoli","doi":"10.1016/j.trgeo.2024.101407","DOIUrl":"10.1016/j.trgeo.2024.101407","url":null,"abstract":"<div><div>Fiber-reinforced shotcrete is a high-performance material that presents some special characteristics, which can provide some suitable applications in the excavation of underground cavities. The presence of fibers induces an increase in the tensile strength, flexural strength and shear strength in the concrete, as well as allowing a ductile rather than brittle type of behavior. It can be used to create a lining of the underground cavity that allows the stabilization of rock blocks that show a tendency to slip or fall (from the side walls or from the crown area, respectively). In this work, some full-scale tests on the fiber-reinforced shotcrete lining are presented. From these tests, it was possible to measure the behavior of this material when it is loaded locally: it is the same type of action produced by the rock block when it is held back from falling or slipping. The results obtained have allowed to characterize this type of material from a mechanical point of view. A subsequent detailed analysis of the stability of rock blocks surrounding an underground cavity permitted to determine the static stabilizing contribution offered by the fiber-reinforced shotcrete lining, leading to the definition of the minimum thickness required, in relation to the type of block that is present (shape and size). It was possible to predict how a lining thickness of about 3.5 cm is able to stabilize (just 15 min after its spraying) rock blocks with an exposed surface area of up to 10 m<sup>2</sup> and a distance of the internal vertex from the border of the cavity of up to 3 <em>m</em>.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101407"},"PeriodicalIF":4.9,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532861","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

The impact of Microbially Induced Calcite Precipitation (MICP) on sand internal erosion resistance: A microfluidic study 微生物诱导方解石沉淀（MICP）对沙子内部抗侵蚀性的影响：微流控研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CIVIL

Transportation Geotechnics

Pub Date : 2024-10-15 DOI: 10.1016/j.trgeo.2024.101404

Kaifang Li, Yuze Wang

Fine particle internal erosion involves the detachment, transport, and deposition of fine particles within soil, significantly impacting agriculture, engineering, and environmental protection. Microbially induced calcite precipitation (MICP) has proven to be an effective method for controlling internal erosion. To optimize MICP protocols for effective erosion control, understanding the microscopic mechanisms by which MICP reduces fine particle erosion is essential but remains unclear. In this study, microfluidic chip experiments were conducted to observe the characteristics of calcium carbonate crystals and fine particles before and after MICP reinforcement and erosion. Through quantitative analysis of the calcium carbonate produced by MICP and eroded fine particles, the effects of bacterial density, concentration of cementation solution, and flow rate on the efficiency of MICP in resisting soil internal erosion were investigated. In addition, three primary mechanisms by which MICP reduces fine particle erosion were identified. Firstly, in situ sand stabilization occurs when calcium carbonate generated by MICP bonds and encapsulates fine particles, forming larger particles that remain stable under erosive flow conditions. Secondly, regional sand stabilization is achieved as MICP-produced calcium carbonate crystals narrow or block the flow channels, preventing extensive migration of fine particles. Lastly, adjacent particle stabilization is facilitated by calcium carbonate crystals, which remain stable during water flow erosion and alter the erosion flow lines, creating zones adjacent to the crystals where fine particle movement is minimized. These findings provide a deeper understanding of the role of MICP in erosion control and can inform the development of more effective erosion mitigation strategies.

细颗粒内侵蚀涉及土壤中细颗粒的剥离、迁移和沉积，对农业、工程和环境保护产生重大影响。事实证明，微生物诱导方解石沉淀（MICP）是控制内侵蚀的有效方法。为了优化 MICP 方案以有效控制侵蚀，了解 MICP 减少细颗粒侵蚀的微观机制至关重要，但目前仍不清楚。本研究通过微流控芯片实验观察了 MICP 加固和侵蚀前后碳酸钙晶体和细颗粒的特征。通过对 MICP 产生的碳酸钙和被侵蚀的细颗粒进行定量分析，研究了细菌密度、固结溶液浓度和流速对 MICP 抵抗土壤内部侵蚀效率的影响。此外，还确定了 MICP 减少细颗粒侵蚀的三个主要机制。首先，当 MICP 产生的碳酸钙粘合并包裹细颗粒，形成较大的颗粒并在侵蚀性流动条件下保持稳定时，就会发生原地固沙。其次，当 MICP 产生的碳酸钙晶体缩小或堵塞流道，阻止细颗粒的大范围迁移时，就实现了区域固沙。最后，碳酸钙晶体在水流侵蚀过程中保持稳定，并改变侵蚀流线，在晶体附近形成细颗粒移动最小的区域，从而促进了邻近颗粒的稳定。这些发现加深了人们对 MICP 在侵蚀控制中的作用的理解，可为制定更有效的侵蚀缓解战略提供参考。

{"title":"The impact of Microbially Induced Calcite Precipitation (MICP) on sand internal erosion resistance: A microfluidic study","authors":"Kaifang Li, Yuze Wang","doi":"10.1016/j.trgeo.2024.101404","DOIUrl":"10.1016/j.trgeo.2024.101404","url":null,"abstract":"<div><div>Fine particle internal erosion involves the detachment, transport, and deposition of fine particles within soil, significantly impacting agriculture, engineering, and environmental protection. Microbially induced calcite precipitation (MICP) has proven to be an effective method for controlling internal erosion. To optimize MICP protocols for effective erosion control, understanding the microscopic mechanisms by which MICP reduces fine particle erosion is essential but remains unclear. In this study, microfluidic chip experiments were conducted to observe the characteristics of calcium carbonate crystals and fine particles before and after MICP reinforcement and erosion. Through quantitative analysis of the calcium carbonate produced by MICP and eroded fine particles, the effects of bacterial density, concentration of cementation solution, and flow rate on the efficiency of MICP in resisting soil internal erosion were investigated. In addition, three primary mechanisms by which MICP reduces fine particle erosion were identified. Firstly, <em>in situ</em> sand stabilization occurs when calcium carbonate generated by MICP bonds and encapsulates fine particles, forming larger particles that remain stable under erosive flow conditions. Secondly, regional sand stabilization is achieved as MICP-produced calcium carbonate crystals narrow or block the flow channels, preventing extensive migration of fine particles. Lastly, adjacent particle stabilization is facilitated by calcium carbonate crystals, which remain stable during water flow erosion and alter the erosion flow lines, creating zones adjacent to the crystals where fine particle movement is minimized. These findings provide a deeper understanding of the role of MICP in erosion control and can inform the development of more effective erosion mitigation strategies.</div></div>","PeriodicalId":56013,"journal":{"name":"Transportation Geotechnics","volume":"49 ","pages":"Article 101404"},"PeriodicalIF":4.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142532408","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}

引用次数: 0