Discussion on face slab pouring time of high concrete face rockfill dam

In order to avoid large or non-uniform deformation of rockfill after face slab placement,it is proposed to analyze and sort out the early monitoring data of rockfill filling,and compare the advantages and disadvantages of Duncan model,two-yield surface elastic-plastic model and Tsinghua non-linear K-G model applied in rockfill dams.Based on the measured data at early construction,the constitutive model reflecting actual status of rockfill in specific conditions is determined.In combination with genetic algorithm,the BP neural network is used to back calculate the optimal parameters of the model,then analyze and calculate the predicted rockfill settlement and deformation during construction.By analysis and comparison of the predicted settlement and deformation with the measured settlement and deformation of the completed rockfill,and taking the predicted settlement and deformation of rockfill for reference,the settlement period is rationally prepared in advance and face slab placement time is reasonably determined so as to prevent negative influence of large rockfill settlement and deformation on the face slabs and improve the stress and deformation of face slabs.