3-D FEM Simulation Of Transient Temperature And Stress Fields Of Bulky Concrete And Analysis Of Cracking Mechanism

Concentrated on simulative analysis of 3-D temperature and stress fields of concrete dams, determination of thermodynamic parameters, cracking mechanism, crack prevention , crack control and crack repairs ,the mainly work in this dissertation are as follows:1. According to the characteristics of concrete dams constructed with multi-layers and multi-blocks, a bilinear transitional 10-node element or 12 node element model and a multi-laminate element model are proposed. The incompatible problem among the blocks in calculation with normal FEM is solved by using the transitional element model. The scale of FEM calculation is essentially reduced by use of the multi-laminated element model and the calculation precision is high. A special simulative program of 3-D FEM is designed and implemented based on the above ways.2. A back analysis method for parameter identification of materials is suggested and practiced combining analytic solutions or FEM solutions with optimal mathematic method. An experiment of temperature field of a concrete block is made for a practical project, and the back analysis for unknown parameters is carried out successfully.3. The causes of the concrete cracking the measures for temperature control and crack repairs are expatiated.4. Through the example of the practical project, the 3-D simulative calculations of transient temperature and stress fields of the concrete structure are conducted based on the practical construction scheme. Study on the mechanism of the concrete cracking is made and the corresponding methods of. crack repairing are also discussed deeply.