Study On Structure Optimization Of Wall And Curtain Combination Anti-seepage System In Deep Sand And Gravel Layer

Recent years,with the development of the hydropower construction in southwestern china,mang hydroelectric engineering has confronted with difficultie of anti-seepage in deep sand and gravel foundation. Successful application of wall and curtain Combination resolved those problem.Becouse of cutoff wall anti-seepage effect better than grouting curtain,it is as far as possible to upper cutoff wall in the design.But the building cost and construction period of cutoff wall are significantly higher than grouting curtain. This design idea not only results in ovre-consevative,but also increasing the construction difficulty and building cost.Therefore,in the time of construction to wall and curtain combination anti-seepage system,it not only meets the anti-seepage and safety ruquirement,but also pays attention to construcion economy and effectiveness.It is very important realistic significance for the study on structure optimization of wall and curtain combination anti-seepage system in deep sand and gravel layer.Based on above existing problems,this paper carrys out the research from following points which around the structural arrangrment size of wall and curtain combination anti-seepage system in deep sand and gravel layer.(1) First, based on the principles and methods of the optimization design ,according to the structural arrangrment size of wall and curtain combination anti-seepage system,aiming at the construcion safety and effectiveness, Optimization model is established using add weight multi-objective function optimization methods and mathematical normalization method. Then, this paper studies the influence law of optimization depth which comes from variation on the parameters, which combined with parameter sensitivity analysis methods to calculate the duration index and weight ratio of parameters. Finally, according to the project, it selects the appropriate calculation parameters to optimization calulation.(2) Setting up three-dimensional finite element model under the the structural optimization arrangrment size of wall and curtain combination anti-seepage system, working out the calculation of seepage, and analysising the seepage stability of the dam and dam foundation.(3)On the basis of optimization calulation analysis and during optimization depth and practical construction depth, finite element method on the numerical simulation and sensitivity analysis method are used to calculate stress and displacement of anti-seepage system in different lap length ,analysing and inducing variation regulation that is lap length of anti-seepage system following arrangrment size of wall and curtain.By the above optimization calulation analysis,as long as optimization model is reasonable and convergence of calulation method is fast and reliable, optimization results keeps rationality. With the increment of the arrangrment size of wall, optimization lap length of anti-seepage system remain linear increase in a certain range.This paper would be provide some instructive suggestions to design and construction of practical engineering,and also giving reference of theory and method to study on structure optimization of wall and curtain combination anti-seepage system in deep sand and gravel layer in future.