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44 results on '"Tan, Yaosheng"'

20. Method for Determining the Fracture Parameters of Fully Graded Dam Concrete.

Author

Gao, Xiaofeng, Wu, Jiong, Zhou, Mengxia, Xu, Tao, Liu, Chunfeng, Tan, Yaosheng, Yang, Ning, and Qiao, Yu

Subjects
STANDARD deviations, CONCRETE fractures, CONCRETE dams, DAMS
Abstract

This paper describes a method for determining the initiation and unstable toughness of fully graded concrete of arbitrary specimen size. The method first predicts the initiation and peak loads of concrete specimens of any size, as well as crack length-to-height ratios based on the fracture test results of concrete specimens with limited sizes or crack length-to-height ratios. Then, combined with the fracture extreme theory, the fracture toughness of concrete with varying size or crack length-to-height ratios is determined. Finally, in order to verify the applicability of the method, it is used to calculate the fracture toughness of small aggregate concrete and fully graded concrete with different sizes or crack length-to-height ratios, and its prediction accuracy is evaluated through indices such as mean absolute percentage error, root mean square error and reliability index a15. The results show that the proposed method can meet the needs of practical engineering applications and can provide theoretical basis for the optimization of the fracture test method of fully graded concrete and the determination of fracture parameters in crack stability or propagation analysis. [ABSTRACT FROM AUTHOR]

Published
2023
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38. Study on the gallery structure cracking mechanisms and cracking control in dam construction site

Author

Ning Zeyu, Peng Lin, Chen Wenfu, Chang Liu, Tan Yaosheng, and Jie Shi

Subjects
business.industry, General Engineering, 020101 civil engineering, 02 engineering and technology, Computational fluid dynamics, Finite element method, 0201 civil engineering, Arch dam, Structural factor, Cracking, 020303 mechanical engineering & transports, Complex geometry, 0203 mechanical engineering, Environmental science, General Materials Science, Geotechnical engineering, Material properties, business, Stress concentration
Abstract

Gallery cracking often occurs during the construction and operation periods of dams. It is very important to implement cracking control measures through the whole dam design, construction, and management process. In this study, a case study is conducted to investigate the gallery cracking mechanisms, risks, and controls of a super-high arch dam during the construction period. By employing 3D finite element methods (FEM), 3D computational fluid dynamics (CFD), and site monitoring, the cracking risks and mechanisms of the gallery are studied relating to different factors of the material properties, structure design, foundation settlement, and environment. The results show that the stress concentration due to the complex geometry and the air temperature drop is the main structural factor and environmental factor, respectively. The wind will spread and reach an extreme speed at the intersection of the gallery if the entrance is not closed, which may accelerate the air temperature drop and the humidity loss at the surface of the gallery. Based on the cracking mechanism analysis and the risk control investigation, a set of engineering procedures is proposed to control and prevent the gallery cracking through optimizing the design theory, the construction methods, and the management philosophy. The application results in the further construction of the super-high arch dam verify the effectiveness of the engineering procedure in the cracking control of similar galleries.

Published
2021

40. Optimization study on super-high arch dam temperature control standard and measure

Author

Liu Youzhi, Zhang Guoxin, Chen Wenfu, Li jintao, and Tan Yaosheng

Subjects
Temperature control, business.industry, Measure (physics), Structural engineering, business, Arch dam, Mathematics
Abstract

Currently, for several super-high arch dams under construction which have caused a series of issues after being strict with temperature control standards, this paper has a sensitivity analysis through a variety of programs and a systematic study about the impact which the highest temperature, the cooling height, the same cooling zone height and other key factors have on the temperature stress of the construction period dam, and then proposes that the temperature control standard and the selection of measures of the ultra-high arch dam are relatively stricter than the regulatory requirements of the traditional dam as long as we have a reasonable control about the temperature drop on the time domain and the temperature gradient on the spatial domain. However we need not make all the dams as a constraint zone to have a temperature stress control. After separated from the basis constraints zone, the maximum temperature of the dam can increase 3-4 °C at least. In addition, while the dam’s same cooling zone height is controlled by the 0.2L (L for the bottom width), it can meet the requirements for filling and anti-cracking without using two cooling areas. This finding will help reduce the difficulty of height control of the cantilever when the dam is under construction.

Published
2020

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