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Computers and Concrete
  Volume 24, Number 5, November 2019 , pages 459-468
DOI: https://doi.org/10.12989/cac.2019.24.5.459
 


Experimental and numerical investigation on bearing mechanism and capacity of new concrete plug structures
Yonghong Weng, Shuling Huang, Tangjin Xu and Yuting Zhang

 
Abstract
    The stability and safety of concrete plug structure of diversion tunnel is crucial for the impoundment of upstream reservoir in hydropower projects. The ongoing Wudongde hydropower plant in China plans to adopt straight column plugs and curved column plugs to replace the traditional expanded wedge-shaped plugs. The performance of the proposed new plug structures under high water head is then a critical issue and attracts the attentions of engineers. This paper firstly studied the joint bearing mechanism of plug and surrounding rock mass and found that the quality and mechanical properties of the interfaces among plug concrete, shotcrete, and surrounding rock mass play a key role in the performance of plug structures. By performing geophysical and mechanical experiments, the contact state and the mechanical parameters of the interfaces were analyzed in detail and provide numerical analysis with rational input parameters. The safety evaluation is carried out through numerical calculation of plug stability under both construction and operation period. The results indicate that the allowable water head acting on columnar plugs is 3.1 to 7.4 times of the designed water head. So the stability of the new plug structure meets the design code requirement. Based on above findings, it is concluded that for the studied project, it is feasible to adopt columnar plugs to replace the traditional expanded wedge-shaped plugs. It is hoped that this study can provide reference for other projects with similar engineering background and problems.
 
Key Words
    new plug structure; straight column plug; curved column plug; numerical simulation; bearing mechanism; adaptability evaluation
 
Address
Yonghong Weng: Changjiang Institute of Survey, Planning, Design and Research, Wuhan, 430010, China
Shuling Huang: Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources, Yangtze River Scientific Research Institute, Wuhan, 430010, China
Tangjin Xu: Changjiang Institute of Survey, Planning, Design and Research, Wuhan, 430010, China
Yuting Zhang: Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources, Yangtze River Scientific Research Institute, Wuhan, 430010, China
 

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