Rapid estimation of resilient modulus of subgrade soils using performance-related soil properties
作者：
Zhang, Junhui;Peng, Junhui;Zeng, Ling* ;Li, Jue;Li, Feng
期刊：
International Journal of Pavement Engineering ,2021年22(6):732-739 ISSN：1029-8436
通讯作者：
Zeng, Ling
作者机构：
[Zhang, Junhui; Peng, Junhui; Zeng, Ling; Li, Jue; Li, Feng] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha, Hunan, Peoples R China
通讯机构：
[Zeng, Ling] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha, Hunan, Peoples R China.
关键词：
Forecasting;Predictive analytics;Regression analysis;Road construction;Soil moisture;Multiple regression analysis;Repeated load triaxial tests;Resilient modulus;Soil property;Subgrade soil;Soil testing
摘要：
This study aims at developing an efficient and accurate methodology to estimate the resilient modulus of subgrade soils. First, a new resilient modulus model incorporating stress dependence and moisture dependence was proposed. Second, prediction models were developed to conveniently and accurately determine model parameters of SWCC and resilient modulus model. In order to characterise the moisture dependence of subgrade soils, the matric suction was added into the proposed model. The matric suction was measured by the pressure plate test and the soil-water characteristic curve (SWCC) was used to determine the matric suction value at any given moisture contents. In order to develop prediction models for model parameters of SWCC and resilient modulus model, the laboratory experiments and multiple regression analysis were conducted on 22 soil samples. A series of performance-related soil properties were measured and used to develop the coefficients prediction models. The developed coefficients prediction models using the performance-related soil properties have high R-squared values and were validated by comparing the measured and predicted values of resilient modulus. Therefore, when the basic physical properties of soils were obtained, the resilient modulus can be predicted for the subgrade soils at any given matric suctions and stress states.
语种：
英文
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Laboratory Evaluation and Design of Construction and Demolition Wastes for Granular Base
作者：
Yi, Jin;Liang, Chenghao* ;Qian, Junfeng;Li, Jue;Yao, Yongsheng
期刊：
Advances in Civil Engineering ,2020年2020:1-10 ISSN：1687-8086
通讯作者：
Liang, Chenghao
作者机构：
[Qian, Junfeng; Yi, Jin; Yao, Yongsheng; Liang, Chenghao] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.;[Li, Jue] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410114, Peoples R China.
通讯机构：
[Liang, Chenghao] C;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.
摘要：
<jats:p>Using recycled aggregate from construction and demolition (C&D) wastes as a construction material is a potential method for solving the disposal of C&D wastes, which can reduce the exploitation of natural aggregate. In this study, extensive laboratory tests were carried out to investigate the reliability of the C&D wastes used as road base material. Meanwhile, the gradation design and the dominant aggregate size range were considered, and a physical disposal method was proposed to enhance the structural performance of the recycled material by replacing the skeleton of the recycled aggregate (RA) with high-quality limestone. The test results showed that (1) given the high absorbency and fragility of C&D wastes, its RA was not enough to provide the strength and stability required by the base; (2) the compaction characteristics of the RA are quite different from that of the limestone aggregate, but the final compaction effect is basically the same; (3) the replacement treatment proposed in this study is an effective approach to improve the performance of the recycled granular base because the breakage rate decreased by at least 28.2% and the mechanical properties increased by approximately 50% compared with that of the untreated specimen; and (4) when the limestone content reached 75%, the California bearing ratio and the resilient modulus of the graded B specimen exceeded 120% and 200 MPa, respectively, satisfying the pavement requirement in medium traffic.</jats:p>
语种：
英文
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基于文本挖掘的高处坠落事故致因及关联规则分析
作者：
李珏;李世杰
期刊：
长沙理工大学学报(自然科学版) ,2020年17(2):61-67+74 ISSN：1672-9331
作者机构：
长沙理工大学 交通运输工程学院,湖南 长沙 410114;[李珏; 李世杰] 长沙理工大学
关键词：
文本挖掘;高处坠落事故;事故致因;R语言;TF-IDF算法;关联规则;Apriori算法
摘要：
高处坠落事故是建筑业中最常见的事故之一。为明确高处坠落事故致因,找到有效的事故预防措施,搜集了2012~2017年国内528例高处坠落事故调查报告,以R语言为平台,结合文本挖掘技术确定了事故中的32项事故致因,其中包括7项关键事故致因。利用Apriori算法挖掘出事故致因之间的关联规则,通过可视化关联规则结果,得到了高处坠落事故发生过程中的事故致因因果关系,为高处坠落事故的预控提供参考。
语种：
中文
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基于文本挖掘的建筑施工高处坠落事故致因网络分析
作者：
李珏;王幼芳
期刊：
安全与环境学报 ,2020年20(04):1284-1290 ISSN：1009-6094
作者机构：
长沙理工大学交通运输与工程学院,长沙410000;[李珏; 王幼芳] 长沙理工大学
关键词：
安全管理工程;建筑施工;高处坠落;文本挖掘;社会网络分析
摘要：
为明确建筑施工过程中高处坠落事故的致因及其之间的联系,选取2012—2018年国内558例建筑施工高处坠落事故调查报告,借助文本挖掘和社会网络分析的方法,对事故报告进行分词处理、特征选择后,得到致因特征项、致因网络及致因集合,并利用词云和网络结构图等方法对结果进行可视化展示。结果表明,文本挖掘所得的28项致因中,7项致因位于致因网络的核心区域,基于该7项致因分别构建了致因集合,为建筑施工高处坠落事故的预控提供参考。
语种：
中文
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基于社会技术系统的高处坠落事故致因关联性研究
作者：
李珏;刘焕;王幼芳;候云飞
期刊：
铁道科学与工程学报 ,2020年17(02):524-532 ISSN：1672-7029
作者机构：
长沙理工大学交通运输工程学院,湖南长沙,410014;[候云飞; 李珏; 王幼芳; 刘焕] 长沙理工大学
关键词：
高处坠落;社会技术系统;宏观工效学模型;事故致因;社会网络分析;潜在类别分析
摘要：
为系统分析高处坠落事故的产生机理,运用社会技术系统理论,分析个人子系统、技术子系统、组织管理子系统和环境子系统对事故发生的影响;通过文献分析、事故研究和专家讨论识别35个影响事故发生的致因因素,建立高处坠落事故宏观工效学模型(MM);再根据201份事故报告数据,运用社会网络分析(SNA)构建高处坠落事故致因关系网络,分析网络的中心度情况;采用潜在类别模型(LCA)分析主要致因的整体交互作用。研究结果表明:高处坠落事故关系网络中,存在40~64岁的普通工人、安全教育培训不到位和工人违规操作等核心节点,防坠落系统,护栏或安全网不合格等纽带节点,感知与决策失误等独立发挥作用节点;高处坠落事故存在4类典型MM,得出各类模型中主要致因的交互作用。综合各因素间相关性,提出针对性的高处坠落事故干预对策。
语种：
中文
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Compaction process tracking for asphalt mixture using discrete element method
作者：
Qian, Guoping;Hu, Kaikai;Li, Jue* ;Bai, Xianping;Li, Ningyuan
期刊：
Construction and Building Materials ,2020年235:117478 ISSN：0950-0618
通讯作者：
Li, Jue
作者机构：
[Qian, Guoping; Li, Jue; Hu, Kaikai; Bai, Xianping] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha, Hunan, Peoples R China.;[Li, Ningyuan] Univ Waterloo, Dept Civil & Environm Engn, Waterloo, ON, Canada.
通讯机构：
[Li, Jue] C;Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha, Hunan, Peoples R China.
关键词：
Asphalt mixture;Compaction method;Air void content;Critical aggregate size;Large-scale specimen;Discrete element method
摘要：
Although the same compaction degree is achieved in practice, asphalt mixture samples prepared by different compaction methods often have different mechanical properties. In this paper, the air void content (AV) and distribution of aggregates and asphalt mortar in the process of asphalt mixture compaction are traced to capture the meso structural change characteristics of asphalt mixture during compaction. Using the discrete element method (DEM), a numerical technique is developed to simulate the laboratory compaction by taking into account the critical aggregate size and boundary effect. First, the critical aggregate size (CAS) is determined by the 2D and 3D binary particle assembly. Second, DEM simulations of both the Marshall impact compaction (MIC) and static compaction (SC) methods are conducted by the mass-wall and servo boundary, respectively. Third, the applicability of the 2D model is demonstrated through laboratory tests and numerical calculations. Finally, the distribution of aggregates and asphalt mortar are displayed and analyzed. The results show that the variation of CAS presents linear growth approximately with the increase of coarse particle size, less affected by the boundary. The primary control sieve (PCS) is applicable to separate the coarse and fine particles in the 3D assembly, but the CAS is around 0.195 for the 2D assembly, which is obviously less than the PCS. It is verified by two compaction methods and two mixture gradations that the DEM simulation is an effective way to evaluating the compacting effects of the compaction process. By double-sided hammering, coarse aggregates are moved to accumulate more closely, thus the coordination number at the bottom increases. Although a dense specimen can be achieved by compaction method, the size distribution of particles is still uneven in horizontal direction, since the position of large size particles (>16 mm) is difficult to be changed in the compaction process. (C) 2019 Elsevier Ltd. All rights reserved.
语种：
英文
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Characteristics of Deformation and Damping of Cement Treated and Expanded Polystyrene Mixed Lightweight Subgrade Fill under Cyclic Load
作者：
Lu, Weihua;Miao, Linchang;Zhang, Junhui* ;Zhang, Yongxing;Li, Jing
期刊：
Applied Sciences-Basel ,2019年9(1):167 ISSN：2076-3417
通讯作者：
Zhang, Junhui
作者机构：
[Lu, Weihua; Zhang, Yongxing] Nanjing Forestry Univ, Sch Civil Engn, Nanjing 210037, Jiangsu, Peoples R China.;[Miao, Linchang; Li, Jing] Southeast Univ, Inst Geotech Engn, Nanjing 210096, Jiangsu, Peoples R China.;[Zhang, Junhui] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410114, Hunan, Peoples R China.
通讯机构：
[Zhang, Junhui] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410114, Hunan, Peoples R China.
关键词：
Axial accumulative strain;Cyclic load;Damping ratio;EPS lightweight soil;Resilient modulus
摘要：
To investigate the deformation and damping characteristics of cement treated and expanded polystyrene (EPS) beads mixed lightweight soils, this study conducted a series of triaxial shear tests cyclic loading for different confining pressures, cement contents, and soil categories. Through repeated loading and unloading cycles, axial accumulative strain, resilient modulus, and damping ratio versus axial total strain were analyzed and the mechanical behavior was revealed and interpreted. Results show that the resilient modulus increases with increasing confining pressure and cement content. A decreasing power function can be used to fit the relationship between the resilient modulus and the axial total strain. Although sandy lightweight specimens usually own higher resilient modulus than silty clay lightweight specimens do, the opposite was also found when the axial total strain is larger than 8% with 50 kPa confining pressure and 14% cement content. For damping ratio the EPS beads mixed lightweight soil yields a weak growth trend with increasing axial total strain and a small reduction with higher confining pressure and cement content. For more cementations, the damping ratio of the sandy lightweight soil is always smaller than the silty clay lightweight soil. Nonetheless, the differences of damping ratios that were obtained under all of the test conditions are not significant. © 2019 by the authors.
语种：
英文
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Calculation and Control Methods for Equivalent Resilient Modulus of Subgrade Based on Nonuniform Distribution of Stress
作者：
Yao, Yongsheng;Qian, Junfeng;Li, Jue* ;Zhang, Anshun;Peng, Junhui
期刊：
Advances in Civil Engineering ,2019年2019:1-11 ISSN：1687-8086
通讯作者：
Li, Jue
作者机构：
[Qian, Junfeng; Yao, Yongsheng] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;[Peng, Junhui; Li, Jue; Zhang, Anshun] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Li, Jue] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410083, Hunan, Peoples R China.
摘要：
The resilient modulus of subgrade is a design parameter of the pavement structure, which is significantly affected by the overlying load and traffic load. It is important to calculate the equivalent resilient modulus of the top surface of subgrade based on the nonuniform distribution of resilient modulus in subgrade. This paper takes the fully weathered granite soil as the research object. Firstly, the soil density of different layers of the subgrade structure is calculated by the degree of compaction of different subgrade layers. Secondly, the overlying load of each point in the subgrade is determined based on the quality of subgrade. Thirdly, the subprogram of the finite element software is compiled and redeveloped based on the elastic constitutive model, and the calculation method for the resilient modulus of each point in the subgrade under the traffic load is proposed when the convergence criterion is set up. Finally, according to the deflection equivalence of the elastic double layer and elastic half-space, the calculation and control methods for equivalent resilient modulus of the top surface of subgrade under nonuniform stress distribution are put forward, and the field verification tests are carried out. The results show that the error range between numerical calculation and field measurement of equivalent resilient modulus of subgrade is 10%. It shows that the calculation method for equivalent resilient modulus of subgrade proposed in this study is reasonable and effective. The equivalent resilient modulus of subgrade decreases with the increase of traffic load. And the resilient modulus of subgrade soil increases with the increase of subgrade depth. The resilient modulus of subgrade soil has a significant impact on the equivalent resilient modulus of subgrade after the overlaying gravel layer. The equivalent resilient modulus of the subgrade with the gravel layer increases with the increase of the resilient modulus of the subgrade soil. © 2019 Yongsheng Yao et al.
语种：
英文
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基于HFACS的施工触电事故致因的关联性分析与干预对策
作者：
李珏;刘焕
期刊：
长沙理工大学学报(自然科学版) ,2019年16(2):36-41+48 ISSN：1672-9331
作者机构：
长沙理工大学 交通运输工程学院,湖南 长沙,410114;[李珏; 刘焕] 长沙理工大学
关键词：
职业安全;触电事故;事故致因;频率分析;潜在类别分析;干预对策
摘要：
为系统分析施工触电事故致因的潜在联系性,为预防和控制事故发生提供决策依据,基于改进的人因分析和分类系统(HFACS)对84起工程触电致死事故致因辨识分类,并在此基础上采用频率分析和潜在类别分析(LCA)对事故致因进行关联性研究.通过研究分析发现触电事故三大致因:组织过程漏洞、监督不充分和技术环境差;以及潜在三大事故链:管理文化缺失、运行计划不适当和不合格的工作人员,并有针对性地提出了相应的干预对策.
语种：
中文
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Three-dimensional simulation of aggregate and asphalt mixture using parameterized shape and size gradation
作者：
Li, Jue;Zhang, Junhui* ;Qian, Guoping;Zheng, Jianlong;Zhang, Yuqing
期刊：
Journal of Materials in Civil Engineering ,2019年31(3) ISSN：0899-1561
通讯作者：
Zhang, Junhui
作者机构：
[Zhang, Junhui; Qian, Guoping; Li, Jue; Zheng, Jianlong] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410205, Hunan, Peoples R China.;[Zhang, Yuqing] Aston Univ, Sch Engn & Appl Sci, Aston Inst Mat Res, Birmingham B4 7ET, W Midlands, England.
通讯机构：
[Zhang, Junhui] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410205, Hunan, Peoples R China.
关键词：
Aggregates;Aspect ratio;Compression testing;Finite difference method;Geometry;Mechanical variables measurement;Mixtures;Parameterization;Probability distributions;Space-based radar;Vector spaces;Virtual reality;3-D numerical modeling;Correlation coefficient;Geometric characteristics;Irregular aggregates;Parameterized;Three dimensional simulations;Threedimensional (3-d);Uni-axial compression tests;Asphalt mixtures;aggregate;asphalt;computer simulation;discrete element method;numerical model;parameterization;size distribution;three-dimensional modeling
摘要：
Aggregate occupies at least three-quarters of the volume of asphalt mixture and can significantly affect the performance of pavement. The geometrical morphology influences the slippage and interlock among aggregates for resisting and distributing applied loads. In recent years, the discrete-element method (DEM) has been employed for simulation of asphalt mixture structure. This paper introduces an approach for simulation of aggregate and asphalt mixtures using parameterized shape and size gradation. Both the plane geometry factor (PGF) and the section aspect ratio (SAR) were employed to describe the three-dimensional (3D) geometric characteristics of aggregates. A numerical technique of aggregate models was implemented with probabilistic parameters depending on statistical results of PGFs and SARs. The 3D numerical model of asphalt mixtures was assembled with three different components, and was validated by uniaxial compression tests via comparison with the laboratory result. It was found that the PGF and SAR are appropriate to describe the three-dimensional features of aggregate shapes, because a simplified space object can be described by a two-dimensional (2D) graphical projection and a vector scalar corresponding to the space vector. Probability distribution curves of PGFs and SARs between coarse aggregates were in concordance with the Gauss-type function, because their correlation coefficients were all greater than 95%. It was verified that the developed clumping algorithm of aggregates was reasonable in terms of the shape and size gradation. Based on the parallel-bond model and Burger's model, the results of virtual tests were in good agreement with those of laboratory uniaxial tests. The angularity (PGF) of aggregates has a beneficial effect on the strength and stability of asphalt mixtures, whereas the flat-elongated feature (SAR) has a negative effect on the strength and stability of asphalt mixtures. © 2019 American Society of Civil Engineers.
语种：
英文
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Investigation of the fatigue modulus decay in cement stabilized base material by considering the difference between compressive and tensile modulus
作者：
Lv, Songtao;Yuan, Jiang;Liu, Chaochao* ;Wang, Jiaqing;Li, Jianglong;...
期刊：
Construction and Building Materials ,2019年223:491-502 ISSN：0950-0618
通讯作者：
Liu, Chaochao
作者机构：
[Li, Jianglong; Lv, Songtao; Yuan, Jiang; Zheng, Jianlong; Liu, Chaochao] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410004, Hunan, Peoples R China.;[Wang, Jiaqing; Liu, Chaochao] Michigan Technol Univ, Dept Civil & Environm Engn, 1400 Townsend Dr, Houghton, MI 49931 USA.
通讯机构：
[Liu, Chaochao] C;[Liu, Chaochao] M;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410004, Hunan, Peoples R China.;Michigan Technol Univ, Dept Civil & Environm Engn, 1400 Townsend Dr, Houghton, MI 49931 USA.
关键词：
Cement stabilized macadam;Fatigue damage;Modulus decay;Tensile modulus;Compressive modulus
摘要：
The cement stabilized macadam base experiences tensile and compressive stresses simultaneously in the actual pavement structures, resulting in the influence of stress states on fatigue performance. In this paper, the fatigue performance of cement stabilized macadam was analyzed based on modulus decay considering the difference between compressive and tensile modulus. A synchronous measurement method of tensile and compressive modulus, which based on convention four-point bending test, was utilized to measure modulus of cement stabilized macadam during a fatigue test. The four-point bending fatigue test was conducted upon four different stress levels of 0.25 MPa, 0.5 MPa, 1.0 MPa, and 1.5 MPa. The average of 10 closest modulus values nearby the first 1% of fatigue life was adopted to determine the initial modulus. The last 5 cycles before the failure of the specimen in the fatigue test was determined as the critical modulus value. It was observed from the tests results that the critical value of compressive fatigue modulus was 8 times higher than that of tensile fatigue modulus. The initial and critical values of both tensile and compression decreased with the increase of stress levels. Under different stress levels, the modulus decay mode of tensile and compressive modulus was similar, but the decay rates of tensile modulus were higher than that of compressive modulus. Based on the modulus decay mode, the concept of critical failure point was put forward to characterize the fatigue behavior of cement stabilized macadam. During the fatigue process, both tensile and compressive modulus decay presented three stages, i.e. preliminary stage, stable stage, and rapid attenuation stage. The stable stage of tensile modulus was shorter than that of compressive modulus, which means that the primary fatigue damage occurred in the tensile zone. © 2019 Elsevier Ltd
语种：
英文
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Belt-like MnO2 cathode to enable high energy density and ultra-stable aqueous asymmetric supercapacitor
作者：
Li, Jie;Yin, Minshuai;Guo, Chunli* ;Zhang, Huaiping;Li, Taotao;...
期刊：
Surface and Coatings Technology ,2019年359:175-182 ISSN：0257-8972
通讯作者：
Guo, Chunli
作者机构：
[Wei, Yinghui; Hou, Lifeng; Li, Jie; Yin, Minshuai; Guo, Chunli; Wang, Huaiyan; Li, Taotao; Zhang, Huaiping] Taiyuan Univ Technol, Coll Mat Sci & Engn, Taiyuan 030024, Shanxi, Peoples R China.;[Wei, Yinghui] Taiyuan Univ Sci & Technol, Taiyuan 030024, Shanxi, Peoples R China.;[Jia, Chuankun] Changsha Univ Sci & Technol, Coll Mat Sci & Engn, Changsha 410114, Hunan, Peoples R China.;[Jia, Chuankun] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Hunan, Peoples R China.;[Jia, Chuankun] Nankai Univ, Minist Educ, Key Lab Adv Energy Mat Chem, Tianjin 300071, Peoples R China.
通讯机构：
[Guo, Chunli] T;Taiyuan Univ Technol, Coll Mat Sci & Engn, Taiyuan 030024, Shanxi, Peoples R China.
关键词：
Asymmetric supercapacitor;High energy density;MnO 2;Ultra-stable
摘要：
A belt-like MnO 2 nanomaterials is designed as cathode material to enable neutral aqueous, high energy density and ultra-long life asymmetric supercapacitor. The energy density and power density can reach as high as 33.8 Wh kg −1 and 5000 W kg −1 respectively even in the high-voltage region of 0–2 V. The asymmetric supercapacitor exhibits 91% capacity retention after 10,000 cycles indicating outstanding cycling property. The ultra-stability of the belt-like MnO 2 //activated carbon asymmetric supercapacitor makes it a promising device for large-scale applications. © 2018 Elsevier B.V.
语种：
英文
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Use of colour transformation and the geodesic method for road centreline extraction from VHR satellite images
作者：
Miao, Zelang* ;Gao, Lipeng;He, Yueguang* ;Wu, Lixin;Shi, Wenzhong;...
期刊：
International Journal of Remote Sensing ,2019年40(10):4043-4058 ISSN：0143-1161
通讯作者：
Miao, Zelang;He, Yueguang
作者机构：
[Li, Jia; Wu, Lixin; Miao, Zelang] Cent S Univ, Sch Geosci & Infophys, Changsha 410083, Hunan, Peoples R China.;[Li, Jia; Wu, Lixin; Miao, Zelang] Cent S Univ, Key Lab Metallogen Predict Nonferrous Met & Geol, Changsha, Hunan, Peoples R China.;[Gao, Lipeng] Wuhan Univ, Sch Remote Sensing & Informat Engn, Wuhan, Hubei, Peoples R China.;[Gao, Lipeng; Shi, Wenzhong] Hong Kong Polytech Univ, Dept Land Surveying & Geoinformat, Kowloon, Hong Kong, Peoples R China.;[He, Yueguang] Changsha Univ Sci Technol, Sch Traff & Transportat Engn, Changsha, Hunan, Peoples R China.
通讯机构：
[Miao, Zelang; He, Yueguang] C;Cent S Univ, Sch Geosci & Infophys, Changsha 410083, Hunan, Peoples R China.;Changsha Univ Sci Technol, Sch Traff & Transportat Engn, Changsha, Hunan, Peoples R China.
关键词：
Color;Color image processing;Extraction;Geodesy;Geodetic satellites;Roads and streets;Centreline extraction;Hue saturation values;Kernel Density Estimation methods;Practical solutions;Red green blues;Road extraction method;Satellite images;Very high resolution;Feature extraction;color;geodesy;image resolution;satellite imagery
摘要：
Seed point-based road extraction methods are vital for extracting road networks from satellite images. Despite its effectiveness, roads in very high-resolution (VHR) satellite images are complicated, such as road occlusion and material change. To tackle this issue, this paper proposes to use the colour space transformation and geodesic method. First, the test image is converted from Red-Green-Blue colour space to Hue-Saturation-Value colour space to reduce the material change influence. The geodesic method is subsequently applied to extract initial road segments that link road seed points provided by users. At last, the initial result is adjusted by a kernel density estimation method to produce centred roads. The presented method is quantitatively evaluated on three test images. Experiments show that the proposed method yields a substantial improvement over cutting-edge technologies. The findings in this study shine new light on a practical solution for road extraction from satellite images. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
语种：
英文
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集成进度和风险的价值工程模型在公路工程设计方案优选中的应用研究
作者：
李珏;刘焕
期刊：
中外公路 ,2019年39(3):307-311 ISSN：1671-2579
作者机构：
长沙理工大学交通运输工程学院,湖南长沙,410114;[李珏; 刘焕] 长沙理工大学
关键词：
公路工程;价值工程;风险;进度;方案优选
摘要：
公路工程项目设计方案比选时,传统价值工程(Value Engineering简称VE)模型考虑以最优成本实现项目必要功能,可能会忽略项目进度和风险,从而导致结果偏差,影响评价的科学性.该文在分析方案优选影响因素的基础上,引入进度指标和风险评价,构建改进的价值工程模型,并以公路工程软基处理设计案例进行实证优选分析.模型采用模糊层次分析法评价项目绩效指标和蒙特卡罗(Monte Carlo)模拟方法评价项目综合风险.改进的价值工程模型将为项目利益相关方提供一种方案评选参考方法.
语种：
中文
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Unified fatigue characteristics model for cement-stabilized macadam under various loading modes
作者：
Lv, Songtao;Xia, Chengdong* ;You, Lingyun;Wang, Xiaofeng;Li, Jianglong;...
期刊：
Construction and Building Materials ,2019年223:775-783 ISSN：0950-0618
通讯作者：
Xia, Chengdong
作者机构：
[Li, Jianglong; Xia, Chengdong; Lv, Songtao; Zheng, Jianlong] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410114, Hunan, Peoples R China.;[You, Lingyun] Michigan Technol Univ, Dept Civil & Environm Engn, 1400 Townsend Dr, Houghton, MI 49931 USA.;[Wang, Xiaofeng] Henan Prov Commun Planning & Design Inst Co Ltd, Zhengzhou 450052, Henan, Peoples R China.
通讯机构：
[Xia, Chengdong] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410114, Hunan, Peoples R China.
关键词：
Cement-stabilized macadam;Fatigue characteristics;Loading modes;Road engineering;Unified characterization
摘要：
Cement-stabilized macadam is widely employed as a base-layer of pavement in China, because of its high strength and stiffness. However, fatigue cracking of the cement-stabilized macadam based pavement is prone to occur under multiple traffic loads, which affects the service life of the pavement. The main objective of this work is to reveal the fatigue characteristics of cement-stabilized macadam under various loading modes by developing a unified fatigue characteristics model. To this end, an unconfined compressive strength test, indirect tensile strength test, and four-point bending strength test were conducted for the cement-stabilized macadam samples under various loading rates. A power function was employed to the pattern of variation of strength with loading rates. The stress ratio of the fatigue test associated with the loading rate was obtained and defined as the rate-dependent stress ratio. Also, the fatigue tests under various loading modes were implemented based on the rate-dependent stress ratio and nominal stress ratio. The preliminary laboratory experimental results showed that it is challenging to compare fatigue performance under different loading modes based on nominal stress ratio. However, the problems of uncertainty and non-uniqueness of fatigue characteristics under various loading modes were resolved by employing the idea of rate-dependent stress ratio in the correlation analyses. Based on that, the new strength structure coefficient associated with the loading rate was proposed in this study. Therefore, the proposed research results provided the fundamental understanding of the fatigue resistance design of pavement with semi-rigid base-layer. © 2019 Elsevier Ltd
语种：
英文
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Investigation of thermal asphalt mastic and mixture to repair potholes
作者：
Li, Jiusu* ;Liu, Jianfang;Zhang, Wenbo;Liu, Guanlan;Dai, Lingchun
期刊：
Construction and Building Materials ,2019年201:286-294 ISSN：0950-0618
通讯作者：
Li, Jiusu
作者机构：
[Liu, Jianfang; Li, Jiusu; Dai, Lingchun] Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Hunan, Peoples R China.;[Zhang, Wenbo] JSTI Grp Hunan Engn Survey & Design Co Ltd, Changsha 410000, Hunan, Peoples R China.;[Liu, Guanlan] Norse Veritas, Dublin, OH 43017 USA.
通讯机构：
[Li, Jiusu] C;Changsha Univ Sci & Technol, Sch Traff & Transportat Engn, Changsha 410114, Hunan, Peoples R China.
关键词：
Pothole repair;Thermal asphalt mortar;Thermal asphalt mixture
摘要：
Asphalt pavements maintenance is a critical infrastructure issue. This paper reports on a high thermal conductivity asphalt pavement mastic and mixture. Thermal asphalt mortar (ThAM) produced with asphalt, silicon-carbide (SiC) powder in the presence, and absence, of styrene-butadiene styrene (SBS), was evaluated. Optimal SBS and SiC proportions were determined by optimization and the balance of viscosity, ductility, and temperature stability. The results indicated that SBS and SiC optimum contents were 5% and 10%, respectively. The corresponding penetration (25 °C), ductility (5 °C), and softening point were 44 dmm, 380 mm and 78 °C, respectively. Heat absorption rates for both thermal asphalt (ThA) and traditional asphalt (TrA) were tested and compared. It showed that temperature differences up to 30 °C. Two types of thermal asphalt concrete (ThAC), blending with iron powder or not, were prepared. ThAC performance was systematically evaluated. The dynamic stability achieved 5872 times/mm, whereas the low temperature bending stiffness modulus was 5505 MPa, indicating both the rutting resistance and cracking resistance favorable. The most unfavorable load position was analyzed using a node tracking method, Bond strength was five times of the maximum shear stress. ThAC and TrA mix thermal conductivities were compared. ThAC thermal conductivity was 19.642 W/(m·K), which was four times that of the TrA mix. © 2018 Elsevier Ltd
语种：
英文
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基于动态故障树的高处坠落事故致因分析
作者：
赵宸伶;李珏
期刊：
项目管理技术 ,2019年17(2):61-65 ISSN：1672-4313
作者机构：
长沙理工大学交通运输工程学院,湖南 长沙,410004;[李珏; 赵宸伶] 长沙理工大学
关键词：
高处坠落事故;动态故障树;马尔可夫;二元决策图;概率
摘要：
高处坠落事故作为建筑行业的高发事故,其影响因素较为复杂。以高处坠落事故为对象,采用动态故障树(Dynamic Fault Tree,DFT)模型,以顶事件概率和基本事件概率重要度作为重要参数,结合二元决策图(Binary Decision Diagrah,BDD)和Markov方法分别对故障树模型中的动态子树和静态子树进行定性和定量分析,将所得结果与静态故障树所得结果进行对比分析,并据此提出相应对策。
语种：
中文
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基于拉夫堡ConAC模型的建筑业起重机械事故致因分析
作者：
陈新亮;李珏
期刊：
工程管理学报 ,2019年33(1):117-122 ISSN：1674-8859
作者机构：
长沙理工大学交通运输工程学院,湖南长沙,410014;[李珏; 陈新亮] 长沙理工大学
关键词：
拉夫堡ConAC模型;起重机械;事故致因分析;事故路径网络图
摘要：
为更好地探索分析建筑业起重机械事故原因,以国家住建部网站获取的2012～2017年起重伤害事故部分调查报告为样本,采用拉夫堡ConAC模型,开展建筑业起重设备事故原因调查和分析。同时运用事故路径网络图进一步分析各层原因之间的因果关系。结果表明,建筑业起重机械事故三大致因分别为:动作行为、监督管理、风险管理;追溯到事故发生的本质原因形成如重物坠落打击伤害类型事故链,为建筑企业安全管理提供科学的依据和决策。
语种：
中文
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Gray Correlation Analysis and Prediction on Permanent Deformation of Subgrade Filled with Construction and Demolition Materials
作者：
Zhang, Junhui;Zhang, Anshun* ;Li, Jue;Li, Feng;Peng, Junhui
期刊：
Materials ,2019年12(18):3035- ISSN：1996-1944
通讯作者：
Zhang, Anshun
作者机构：
[Peng, Junhui; Li, Feng; Zhang, Junhui; Li, Jue; Zhang, Anshun] Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410000, Hunan, Peoples R China.
通讯机构：
[Zhang, Anshun] C;Changsha Univ Sci & Technol, Natl Engn Lab Highway Maintenance Technol, Changsha 410000, Hunan, Peoples R China.
关键词：
Compaction;Correlation methods;Demolition;Fillers;Forecasting;Moisture;Moisture determination;Rock pressure;Construction and demolition;Different moisture contents;Gray correlation;Gray correlation analysis;Gray correlation degrees;Permanent deformations;Prediction model;Subgrade;Creep
摘要：
Construction and demolition (C&D) materials obtained from the demolition of buildings are proven to be qualified and sustainable subgrade fillers. The permanent deformation response of subgrade C&D materials under different moisture contents, degrees of compaction, deviator stresses, and confining pressures was revealed by carrying out dynamic triaxial texts. Then, using a four-factor and three-level orthogonal test and by calculating the Gray correlation degree of each factor, the influence degree of each factor on the permanent deformation was determined. The results indicated that two different response types of the permanent deformation of subgrade C&D materials, plastic shakedown and plastic creep, were identified as reason behind the increase in stress levels. Also, according to the Gray correlation analysis results, the permanent deformation of highway subgrade filled with C&D materials is influenced by the deviator stress most significantly, followed by moisture content, degree of compaction, and confining pressure. Finally, a permanent deformation prediction model about this kind of subgrade filler with a reasonable prediction accuracy was proposed. © 2019 by the authors.
语种：
英文
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Integration of Satellite Images and Open Data for Impervious Surface Classification
作者：
Miao, Zelang;Xiao, Yuelong* ;Shi, Wenzhong;He, Yueguang;Gamba, Paolo;...
期刊：
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing ,2019年12(4):1120-1133 ISSN：1939-1404
通讯作者：
Xiao, Yuelong
作者机构：
[Xiao, Yuelong; Li, Jia; Wu, Lixin; Miao, Zelang] Cent S Univ, Sch Geosci & Infophys, Changsha 410083, Hunan, Peoples R China.;[Xiao, Yuelong; Li, Jia; Wu, Lixin; Miao, Zelang] Cent S Univ, Minist Educ, Key Lab Metallogen Predict Nonferrous Met & Geol, Changsha 410083, Hunan, Peoples R China.;[Shi, Wenzhong] Hong Kong Polytech Univ, Dept Land Surveying & Geoinformat, Hong Kong 999077, Peoples R China.;[He, Yueguang] Changsha Univ Sci Thchnol, Sch Traff & Transportat Engn, Changsha 410083, Hunan, Peoples R China.;[Gamba, Paolo] Univ Pavia, Dept Ind & Informat Engn, I-27100 Pavia, Italy.
通讯机构：
[Xiao, Yuelong] C;Cent S Univ, Sch Geosci & Infophys, Changsha 410083, Hunan, Peoples R China.
关键词：
Impervious surface;one class classification (OCC);open data;satellite image
摘要：
Supervised learning is vital to classify impervious surface from satellite images. Despite its effectiveness, the training samples need to be provided manually, which is time consuming and labor intensive, or even impractical when classifying satellite images at the regional/global scale. This study, therefore, sets out to automatically generate training samples from open data, based on the fact that cities and urban areas are nowadays full of individual geo-referenced data, such as social network data. The proposed method consists of automatic generation of training samples based on a filtering process of open data, satellite image pre-processing, and impervious surface detection using one class classification (OCC). Two Landsat-8 Operational Land Imager images were selected to test the proposed method. The results show that the proposed method is effective in impervious surface with good classification accuracy. The findings in this study shine new light on the applications of open data in remote sensing.
语种：
英文
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