Xiao-Bo Wang, Wen-Jie Xu, Bing-Yin Zhang and Qi-Cheng Sun
Rock-fill dams are embankments of compacted free-draining granular earth containing an impervious zone. Earth utilized in such dams often contains a high percentage of large…
Abstract
Purpose
Rock-fill dams are embankments of compacted free-draining granular earth containing an impervious zone. Earth utilized in such dams often contains a high percentage of large particles – hence the term rock-fill. Mass stability of these dams results from friction and particle interactions rather than through a cementing agent binding the particles together. However, high-stress conditions and prolonged exposure to the elements can severely damage rock-fill. Therefore, understanding and modeling rock-fill breakage is important for dam engineering. The purpose of this paper is to improve discontinuous deformation analysis (DDA) techniques for modeling rock-fill breakage, proving the new method using simulations of spherical particle crushing.
Design/methodology/approach
This work models rock-fill as bonded ellipsoid particles, and develops an improved DDA method to model the breakage of particle assemblies. The paper starts by describing the principles of three-dimensional DDA for spherical particles, and then derives the submatrices for normal contact, shear contact, and frictional force. The new algorithm incorporates a bond model with a revised open-close iteration algorithm into the DDA method to simulate particle crushing. To validate the improved DDA method, calculated particle contacts and movements are validated against theoretical results. Finally, this work performs a series of point-loading experimental tests for cement ellipsoid particles of both high and low compression strengths, with the test results compared against the results from corresponding DDA simulations.
Findings
In particle crushing tests, the force and displacement show an approximately linear relationship until the crushing point, at which point low compression ellipsoid particles split into several large pieces while the high-compression particles break into many small fragments. The DDA simulation results are in good agreement with the crushing tests, demonstrating the validity of the DDA method for solving particle crushing problems. Although the improved DDA model is applicable to rock-fill particle crushing studies, some issues remain, particularly in increasing calculation efficiency and performing large-scale computations and long real-time simulations. Future research should address these issues.
Originality/value
A bond model with a revised open-close iteration algorithm is incorporated into the DDA method. The simulated results shed insight into rock-fill crushing mechanisms, an element of concern in engineering practices.
Details
Keywords
Yan-Chun Zhang, Wu-Zan Luo, Ming Shan, Dong-Wen Pan and Wen-Jie Mu
The aims of this study are to conduct a systematic review of public–private partnership (PPP) studies published from 2009 to 2019, to compare the results with Ke et al. (2009) who…
Abstract
Purpose
The aims of this study are to conduct a systematic review of public–private partnership (PPP) studies published from 2009 to 2019, to compare the results with Ke et al. (2009) who reviewed the PPP literature published from 1998 to 2008, and to trace the evolution of the PPP knowledge in the past two decades. This study also presents the possible directions that the PPP research may go towards in the future, arguably.
Design/methodology/approach
This study carried out a top journal-based search to identify the quality PPP articles published from 2009 to 2019. A total of 12 top-tier construction journals were systematically searched in the database of web of science (WOS), from which 279 PPP articles were identified for review.
Findings
The number of the identified articles, the titles of the journals, institutions, the most cited papers, and prevalent research methods were analyzed and compared. The existing PPP studies in construction journals were classified into seven streams. Through analysis of the PPP research status and gaps, five future research directions were revealed.
Originality/value
This study contributes to the current body of knowledge by revealing the research trend of PPP from 2009 to 2019. It presents the change of PPP development trend in the past decade through comparison with Ke et al. (2009). It also reveals the major research streams and points out the directions that the PPP research may go towards in the future. Moreover, this study is helpful to the practice as well. It can enhance the practitioners' understanding of the PPP development in the past decade. In addition, it identified the research institutions contributing the most in the area of PPP, which may serve as valuable reference for practitioners to locate the best institutions for consultancy or collaboration.
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Keywords
Weinan Zheng, Peng Xiao and Andrew Madden
Academic contention occurs when research evidence is amenable to more than one interpretation. China has a long tradition of Shang Que (商榷), in which authors argue for their…
Abstract
Purpose
Academic contention occurs when research evidence is amenable to more than one interpretation. China has a long tradition of Shang Que (商榷), in which authors argue for their preferred interpretation. The modern form of this tradition is the Shang Que article, which often takes the form of research papers in Chinese-language journals and which tends to be question-oriented. Shang Que articles usually take the views of a particular author or article as the focus of independent and complete criticism by another, independent, academic. This paper explains the role of Shang Que articles in Chinese scholarship and their influence on international academia.
Design/methodology/approach
A bibliometric analysis was used to explore the characteristics and evolution of Chinese Shang Que articles using 30,577 articles published between 1979 and 2018. Microsoft Excel and Gephi were used for data analysis and visualization.
Findings
Findings suggest a decline in the number of Shang Que articles and an increase in the number of co-authors. Shang Que articles remained particularly prominent in Philosophy and Humanities and Social Sciences, where they focused on local issues such as classical Chinese, the Sinicization of Marxism and Chinese literature. This suggests that the number of Shang Que articles is related to the degree of internationalization of a research field.
Originality/value
Shang Que articles, which have been influenced by academic paradigms in English, are a fusion of China's Shang Que tradition and of the modern academic system. Through considering Shang Que articles, this paper explores the benefits of local academic traditions in non-English-speaking cultures.