Study On Anti-seepage And Deformation Stability Of High Composite Geomembrances Facing Dam

At the present stage,our country is building a batch of the concret-faced rockfill dam of 300 m.Although domestic concret-faced rockfill dam technology has been in a leading position,there are still some problems such as excessive deformation of rockfill and serious damage of anti-seepage body.Composite geomembranes,as an impermeable body for high dam,can be effectively reduce the construction inconvenience caused by the partition of the panel,and can avoid some problems such as panel cracks,disengaging of face slab,crushing of vertical joint,are strong to adapt the average deformation capability of dam body.In this paper,Combining with the existing problems of high concrete face rockfill dam and the development demand of composite geomembrances facing dam,the author propose a new scheme and use finite element software ABAQUS to do the following work for composite geomembrane and rockfill.Firstly,a complete composite geomembrane scheme is designed according to the engineering survey.Then proposing two schemes to alleviate the stress concentration of composite geomembranes according to the existing research.Slope finishing or Local grouting of rockfill.And then determining the unit type,constitutive model and contact model by discussing the existing constitutive model of rockfill.And using the life and death unit of ABAQUS to simulate the stage construction of the rockfill.According to the composite geomembrances scheme plan design and the reinforcement scheme,three models are established in this paper,including model 1,model 2 and model 3.Through the finite element calculation of these models,the results show that the composite geomembrances scheme is safe during water storage period and operation period,the stress-strain deformation of the composite geomembrances in the storage period is larger than in the period of storage.After repair the slope,the concentration area of the flowing direction stress in the right bank is reduced to the local area of the high part of the upper part by the height of 2/3 of the dam.The range of tensile stress was decreased from 8.2MPa?16.9MPa to 3.46MPa?6.1MPa.there is also a small reduction in the stress concentration area along the direction of the dam.After the local grouting of the rockfill,the stress nephogram of the composite geomembrances along the flow direction has changed a lot.The stress concentration range is reduced to the height of 1/3 of the bank on the right bank,and the range of tensile stress is reduced to 1.25mpa?2.57mpa.the stress deformation of the composite geomembrances and the range of the stress concentration has been significantly improved.