| The concrete face rockfill dam is a type of dam in which the rockfill is set to the main body and the concrete faceplate is disposed on the upstream surface connecting with the toe plate through peripheral seam as the anti-seepage structure.Due to the characteristics of reliable safety,economical cost and good adaptability,when compared with other dam type schemes under complex and severe conditions such as high seismic intensity zone,deep overburden layer,soft rock foundation and high steep slope,concrete face rockfill dam always stands out as the preferred and perfect dam type.Since the introduction of modern rolling technology in the 1980 s,China has completed the first concrete face rockfill dam project,which has a history of more than 30 years.Although the dam construction technology and design theory launched lately,it has developed rapidly and achieved remarkable results.At present,the technical difficulty,engineering scale and maximum dam height of Chinese concrete face rockfill dams are all in the forefront of the world.The construction technology and construction equipment of 200 m high CFRDs have matured and are facing challenges to achieve 300 m extra-high CFRDs.For the concrete face rockfill dam,the faceplate is the first barrier for the dam to prevent water and seepage and the slab joint water-stop is the key facility.It is an important research content to ensure the safety and reliability of the slab joint water-stop structure.Considering the characteristics of large deformation of joint displacement and the load of high head,researching on the performance of high concrete slab dam structure and actively exploring efficient and reliable new type of slab joint water-stop,the main research contents and conclusions of this paper are as follows:(1)The development history and research status at home and abroad of concrete face rockfill dam are introduced.Briefly expound the research progress of slab joint waterstop technology,the development and application of slab joint waterstop materials,and the new concept of dynamic stability and water stop.Based on the analysis of specific engineering cases and scientific research at home and abroad,consider the high concrete surface dam rockfill and considering the characteristics of large displacement of joint displacement and the load of high head,explore efficient and reliable new type of slab joint waterstop actively.(2)The current status of studying the wave-shaped rubber belt and the supporting rubber bar are limited to experimental research.The numerical simulation analysis of the wave-shaped rubber belt is carried out by finite element using ABAQUS software.Calculate the ability of the rubber belt to sustain the three-way joint displacement deformation and the ultimate hydraulic bearing capacity under different working conditions.For the straight-line wave-shaped rubber rubber belt,when the diameter of the supporting rubber bar is 100 mm,it can sustain not less than 2.5MPa water pressure under working condition I and working condition II.For the corner-section rubber belt,in order to ensure that the supporting rubber rod does not fall into the joint,the critical diameter value is 140 mm and it can sustain not less than 2.5MPa water pressure under the working conditions I and II.According to the equivalent area principle,it is recommended to tie together three rubber bars of 100 mm diameter in a structural form.(3)The construction quality of traditional anchored water-stop cover is difficult to guarantee,the installation and fixing process on site is complicated,and it is damaged easily by the freezing and drawing at the severe cold area.A new type of water-stop cover structure bonded to the concrete surface by adhesive is proposed and carried out through indoor model experiment.The results show that the bonding performance of the modified epoxy coating is 11.8%~38.6% higher than that of YEC epoxy coating,which is 34.8%~53.4% higher than that of SK polyurea coating.The shear displacement is the control condition for the new water-stop cover to sustain the three-way joint displacement deformation.The modified epoxy coating is selected as the adhesive and the working conditions are 50 mm shear displacement,100 mm settlement displacement and 50 mm stretch displacement.Although the new water-stop cover bulges with bonding surface are loosened and torn and the edge of the new cover is slightly deformed,there is no influence on the water-stop effect of the new cover and the structure of overall new water-stop cover is not damaged. |
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