Purpose–This method will become a new development trend in subgrade structure design for high speed railways.Design/methodology/approach–This paper summarizes the structural types and design methods of subgrade bed ...Purpose–This method will become a new development trend in subgrade structure design for high speed railways.Design/methodology/approach–This paper summarizes the structural types and design methods of subgrade bed for high speed railways in China,Japan,France,Germany,the United States and other countries based on the study and analysis of existing literature and combined with the research results and practices of high speed railway subgrade engineering at home and abroad.Findings–It is found that in foreign countries,the layered reinforced structure is generally adopted for the subgrade bed of high speed railways,and the unified double-layer or multi-layer structure is adopted for the surface layer of subgrade bed,while the simple structure is adopted in China;in foreign countries,different inspection parameters are adopted to evaluate the compaction state of fillers according to their respective understanding and practice,while in China,compaction coefficient,subsoil coefficient and dynamic deformation modulus are adopted for such evaluation;in foreign countries,the subgrade top deformation control method,the subgrade bottom deformation control method,the subsurface fill strength control method are mainly adopted in subgrade bed structure design of high speed railways,while in China,dynamic deformation control of subgrade surface and dynamic strain control of subgrade bed bottom layer is adopted in the design.However,the cumulative deformation of subgrade caused by train cyclic vibration load is not considered in the existing design methods.Originality/value–This paper introduces a new subgrade structure design method based on whole-process dynamics analysis that meets subgrade functional requirements and is established on the basis of the existing research at home and abroad on prediction methods for cumulative deformation of subgrade soil.展开更多
建筑室内空间的照明环境对人们活动起着至关重要的作用,不适宜的光照条件会影响工作效率。为了解国内外关于照明环境影响工作效率的研究状况,采用文献计量分析法,统计分析了2013—2023年间102篇中国知网数据库中文期刊和109篇Web of Sci...建筑室内空间的照明环境对人们活动起着至关重要的作用,不适宜的光照条件会影响工作效率。为了解国内外关于照明环境影响工作效率的研究状况,采用文献计量分析法,统计分析了2013—2023年间102篇中国知网数据库中文期刊和109篇Web of Science数据库英文期刊,深入研究了现有相关文献的主要研究方向和研究热点演变,系统梳理了照明环境影响工作和学习效率的学术研究动态,总结概括了目前的主要研究方法和成果,为后续该领域的研究提供基础资料和参考。展开更多
为全面了解工程项目风险管理领域的研究现状和发展态势,以Web of Science核心合集数据库2000-2020年收录的1 452篇文献为研究样本,采用文献计量分析法与可视化工具,从刊文数量与发展趋势、作者群体与发文机构、经典期刊与重要文献等层面...为全面了解工程项目风险管理领域的研究现状和发展态势,以Web of Science核心合集数据库2000-2020年收录的1 452篇文献为研究样本,采用文献计量分析法与可视化工具,从刊文数量与发展趋势、作者群体与发文机构、经典期刊与重要文献等层面,剖析工程项目风险管理领域的研究态势。结果表明:近20年的发文量与被引次数呈逐年上升趋势,我国是本领域研究成果贡献最多的国家;Journal of Construction Engineering and Management是发表文章数量最多的热点期刊,排名前10位的研究机构分别来自中国、美国、新加坡、澳大利亚和伊朗;研究热点聚焦于工程项目风险管理的对象、方法和技术应用等主题。展开更多
基金The research was supported by the National Natural Science Foundation of China(Grant Nos.41731288 and 41972299)the Science and Technology Research and Development Program of China Railway(Grant No.P2018G050)+1 种基金the Young Top-Notch Talent Project of National“Ten Thousands Talent Program”(Grant No.2019YJ300)the Major Scientific Research and Development Project of China Academy of Railway Sciences Corporation Limited(Grant No.2019YJ026).
文摘Purpose–This method will become a new development trend in subgrade structure design for high speed railways.Design/methodology/approach–This paper summarizes the structural types and design methods of subgrade bed for high speed railways in China,Japan,France,Germany,the United States and other countries based on the study and analysis of existing literature and combined with the research results and practices of high speed railway subgrade engineering at home and abroad.Findings–It is found that in foreign countries,the layered reinforced structure is generally adopted for the subgrade bed of high speed railways,and the unified double-layer or multi-layer structure is adopted for the surface layer of subgrade bed,while the simple structure is adopted in China;in foreign countries,different inspection parameters are adopted to evaluate the compaction state of fillers according to their respective understanding and practice,while in China,compaction coefficient,subsoil coefficient and dynamic deformation modulus are adopted for such evaluation;in foreign countries,the subgrade top deformation control method,the subgrade bottom deformation control method,the subsurface fill strength control method are mainly adopted in subgrade bed structure design of high speed railways,while in China,dynamic deformation control of subgrade surface and dynamic strain control of subgrade bed bottom layer is adopted in the design.However,the cumulative deformation of subgrade caused by train cyclic vibration load is not considered in the existing design methods.Originality/value–This paper introduces a new subgrade structure design method based on whole-process dynamics analysis that meets subgrade functional requirements and is established on the basis of the existing research at home and abroad on prediction methods for cumulative deformation of subgrade soil.
文摘建筑室内空间的照明环境对人们活动起着至关重要的作用,不适宜的光照条件会影响工作效率。为了解国内外关于照明环境影响工作效率的研究状况,采用文献计量分析法,统计分析了2013—2023年间102篇中国知网数据库中文期刊和109篇Web of Science数据库英文期刊,深入研究了现有相关文献的主要研究方向和研究热点演变,系统梳理了照明环境影响工作和学习效率的学术研究动态,总结概括了目前的主要研究方法和成果,为后续该领域的研究提供基础资料和参考。
文摘为全面了解工程项目风险管理领域的研究现状和发展态势,以Web of Science核心合集数据库2000-2020年收录的1 452篇文献为研究样本,采用文献计量分析法与可视化工具,从刊文数量与发展趋势、作者群体与发文机构、经典期刊与重要文献等层面,剖析工程项目风险管理领域的研究态势。结果表明:近20年的发文量与被引次数呈逐年上升趋势,我国是本领域研究成果贡献最多的国家;Journal of Construction Engineering and Management是发表文章数量最多的热点期刊,排名前10位的研究机构分别来自中国、美国、新加坡、澳大利亚和伊朗;研究热点聚焦于工程项目风险管理的对象、方法和技术应用等主题。
