Research On Engineering Measures For Anti-extrusion Failure Of High Face Rockfill Dams

Concrete face rockfill dams have been widely used in my country's water conservancy projects due to their good adaptability,economy,safety and reliability.With the continuous development of dam construction technology and the improvement of construction machinery,the construction height of concrete face rockfill dams is also increasing.The recently constructed concrete faced rockfill dam has encountered the problem of squeeze failure of the concrete faced rockfill dam,which limits the key technical problems for the further development of concrete faced rockfill dam.Based on the engineering background of the Tianshengqiao 1st face-face rockfill dam,this paper selects the typical years of face-face squeeze failure and analyzes the possible areas and causes of face squeeze failure.Aiming at the possibility of crushing damage of the measured data of the panel,combined with the principle of multi-body nonlinear contact contact rotation effect,the finite element substructure numerical simulation calculation is carried out.Finally,according to the reason of the panel extrusion damage,the engineering measures for the panel to resist extrusion damage are proposed: one measure is to set up soft joints to absorb the extrusion stress between the panels during operation;the other measure is to set up a concrete insulation layer and paint on the surface of the panel Radiation insulation materials,control and reduce concrete temperature and shrinkage and creep cracks.The main research contents are as follows:(1)Based on the typical year data of the crushing failure of the face slab of the Tianshengqiao 1st face rockfill dam,analyze the area and possible causes of the crushing failure of the face slab.(2)For the possible causes of panel squeezing failure of the measured data,the principle of contact rotation effect of multi-body nonlinear contact is introduced,and the reason of panel squeezing is further analyzed through the numerical simulation of the finite element sub-structure.(3)According to the reason of panel extrusion damage,the engineering measures to fill the vertical seam between panels with soft seam materials are proposed.For soft seam materials subjected to strong extrusion stress,material hardening occurs,and a bilinear model is introduced.Through comparative calculations,analyze the effect of filling the vertical seam of the central slab of the river bed with soft seam material on reducing the compression stress of the panel.(4).Regarding the temperature and shrinkage and creep cracks that may occur during the operation and construction periods of the slab,the finite element calculation and analysis of the possible areas and effects of the slab cracks during the construction period are used to compare the installation of concrete insulation layers during the construction period Calculate and analyze the influence of concrete insulation layer on panel cracks,and propose engineering measures.