Deformation Coordination And Workability Prediction Analysis Of Combined Dam Structures With Conventional Concrete And RCC

In recent years,the emergence of new materials and new technologies has provided new ideas for the progress of concrete dam construction.As a new type of dam construction technology,the combined damming of large volume high fly ash content of conventional concrete(CC)and roller compacted concrete(RCC)can give full play to RCC rapid construction,low cost,environmental protection adaptability and other advantages.Combined damming will become an effective way to ease the pressure on schedule.Therefore,it is necessary to put forward systematic and scientific achievements on the key technologies involved in the material,structure design and safe operation of the combined dam,which can be used for reference by other similar projects.In this paper,basing on the actual project,combined with theoretical analysis and engineering practice,a systematic study is carried out on the deformation coordination of CC and RCC on the view of material,the safety prediction of dam deformation on the view of structural and the evolution law of temperature characteristics.The research contents and main achievements are as follows:(1)Driven by the data of mechanical properties of concrete at different parts of the combined dam construction project,the intelligent prediction model of mechanical properties of hydraulic concrete under the combined dam construction form(including compressive strength,splitting tensile strength,elastic modulus,ultimate tensile value and dry shrinkage deformation rate)is established.The accuracy and robustness of the four prediction models are evaluated according to the K-fold cross validation index.The feasibility of the prediction model is verified by comparing the importance of the components obtained from the existing experience and model analysis,which provides a rapid and accurate technical means for hydraulic concrete design.(2)From the perspective of "material" and "structure",and combined with the concept of "deformation coordination",the dynamic deformation characteristics of combined daming materials and structures with different partitions and joints are simulated and analyzed.The mechanical properties of CC with a fly ash content of 20%-50% are obtained by the intelligent prediction model.The meso strength and temperature stress characteristics of the CC-RCC composite specimens are calculated and analyzed by using non-homogeneous finite element method.In addition,modal analysis and elastoplastic analysis under dynamic conditions are carried out,six kinds of partition structure schemes are evaluated from the perspective of deformation coordination,and then the optimized direction of combined damming structure is determined,a more reasonable design scheme is obtained.The above simulation results provide new reference for the design of combined damming materials and structures.(3)Considering the difference of temperature rise characteristics of combined damming materials,an inclined kriging interpolation method is proposed by extending the condition of standard kriging method,and the optimization of inclined parameters is enhanced by using chaotic firefly algorithm and a multi-module,high-precision theoretical system for reconstruction the temperature field of combined damming is established.The effects of four interpolation methods of tilting kriging,standard kriging,primary inverse distance weighting and secondary inverse distance weighting were compared and analyzed.In the six groups of 12 test points,the maximum temperature difference does not exceed 1.11℃.The proposed method has the minimum error range and the predicted results are more stable.(4)An interactive deformation prediction model(IDPM),which combines automatic prediction procedure and background knowledge of dam engineering field is presented.Each decomposition item of the traditional additive model is refactored as the underlying structure of IDPM under Bayesian framework.The artificial custom modeling is also realized by combining parameterized detection and intuitive parameters configuration.By means of visual fitting and statistical indicators to accurately reflect the source of prediction errors,model parameters are further modified to improve the practical applicability.The prediction circulation system of dam deformation composed by the above processes is used to effectively verify and analyze the accuracy,robustness and flexibility of IDPM.The model proposed would provide a novel method for prediction and analysis of the dam deformation safety.