Winter Insulation Research Of The Mass Concrete In Cold Area

Nowadays, mass concrete has been widely used in the construction of civil and hydraulic engineering in our country. At the early design stage, we should put emphasize on the problems of temperature control and crack prevention. Simulation study on concrete temperature control mainly includes the calculation of temperature field and creep stress field,the analysis process is very complex. Self-programming and the commercial finite element method are two main means of simulation calculation. Simulation can provide reasonable theory basis for practical engineering construction, thus avoiding the generation of cracks. Therefore, it is very necessary to have a deep research on the mass concrete temperature creep stress.In this dissertation, firstly, a complete program for calculating temperature field of stratified pouring mass concrete has been comfiled by APDL language of large general finite element analysis commercial software ANSYS. The external changes in temperature, water temperature, surface water, heat preservation material and various boundary conditions have been taken into account. Meanwhile, taking advantage of USERMAT. F and UldFin.F which provided by ANSYS user subroutine, secondary development of ANSYS has been processed. To realizing the calculation of great volume concrete creep stress field,elastic creep constitutive model has been established and the concrete example has proved its validity.Then simulate the heat preservation during winter season of concrete dam engineering instance in winter cold area by using the above program.Different heat preservation solutions for the temperature field and stress field of mass concrete during its construction and operation period have been studied. Make a summary on the rule of concrete dam temperature stress during the construction operation period.According to the research in this paper, during construction and operation period of concrete dam in cold region, winter temperature difference between inside and outside and surface tension stress is large enough to easily produce crack, which are the characteristics of concrete dam long time temperature stress. These problems will seriously affect the safety and durability of dam. Apart from heat preservation in winter season during the period of construction, it is more significant to preserving heat preserve for a long time on its operation time. The conclusions provided some reasonable suggestions for the actual construction of the dam, which also can give some reference for similar projects.