Study on local failure seepage characteristics of anti-seepage face of asphalt concrete faced rockfill dam

Abstract

When the local cracks appear in the anti-seepage face of asphalt concrete face rockfill dam, it will have a great impact on the safety of the dam. In order to understand the influence of local failure of asphalt concrete panel on the seepage of dam body, the asphalt concrete panel rockfill dam in the upper reservoir of a pumping and storage power station in Gansu province were taken as the example, and establishes a three-dimensional finite element model to calculate the seepage field of the dam body when the panel fails locally, and analyzes the influence of local cracks in different parts of the panel and different crack sizes on the seepage field. The result show that the influence of local failure cracks on the seepage field of the dam is mainly concentrated in the vicinity of the cracks. With the increasing of the crack width, the flow through the dam foundation rock mass increases successively, and the seepage slope of the dam foundation rock mass decreases, and the seepage slope of the dam foundation rock mass is basically unchanged. The saturation zone is formed in the small area inside the cushion around the crack of the panel, and the influence of the local failure of the panel on the seepage field does not exceed the cushion zone. The saturation zone and the infiltration flow under the crack are large, so it is extremely important to ensure the gradation and impermeability of the cushion material. At the same time, it is found that the influence of local failure on the seepage field of asphalt concrete panel is related to the failure location and crack width, and the failure location has greater influence on the seepage field than the failure seam width. The result can provide reference for similar engineering design and construction.

Keywords

asphalt concrete face rockfill dam / local failure / saturation region / seepage / three-dimensional finite element