Large Volume Concrete Foundation Floor Jumping Method Finite Element Simulation Research

In recent years,with the rapid development of the economy and the rapid pace of urbanization construction,in recent years,more and more large-scale projects such as high-rise,super high-rise buildings,complex large-scale buildings and underground spaces have emerged.Dominate,and then necessarily involve mass concrete engineering.The construction of large-scale public buildings will inevitably bring about the problem of temperature crack control during the construction of largevolume concrete.There are many solutions to the temperature control of concrete.The jump-jump construction technology is also used as a method to control the temperature control of large-volume concrete.The jump-jump construction technique has a unique advantage in temperature control.However,because the temperature-stress field distribution of the bulk-volume concrete is more complicated and there are many influencing factors,it is difficult to obtain an analytical solution accurately in actual engineering.However,with the rapid development of computer science and numerical calculation methods,there have been many calculation methods that have become computer simulation technology applied to the temperature stress of mass concrete.Based on the theory of concrete temperature field,this paper based on finite element simulation of mass concrete The temperature stress is simulated and analyzed,and its main research work is as follows:(1)Based on the heat conduction theory of concrete,this paper uses the finite element MIDAS/FEA thermal analysis module to simulate the construction process of one-time pouring,layered pouring and jumping tank pouring,and analyzes the general law of concrete temperature field;(2)Through the analysis of the factors affecting the length of the skip warehouse,in general,the comprehensive temperature difference of the concrete and the ultimate tensile of the concrete are the main factors affecting the length of the skip warehouse,and when the comprehensive temperature difference is controlled at about 25 ℃,the length of the skip warehouse Generally it can reach about 50 m.However,under special circumstances,from the theoretical point of view of the calculation of the cell length of the skip position method,it is theoretically believed that there is no fixed uniform value for the cell length,and its value depends on the comprehensive factors affecting the length of the concrete cell;(3)The analysis of the hydration heat of the concrete bottom plate through the size effect shows that: under normal circumstances,the plane size of the mass concrete and the total volume of the concrete have little effect on the internal temperature field and stress field of the concrete.When the material parameters and boundary conditions are exactly the same,the internal temperature value and stress value of mass concrete are only closely related to the thickness dimension.The larger the thickness dimension,the greater the internal temperature peak and stress peak;(4)The causes of mass concrete cracks are complex and diverse.Under the premise of accurately grasping the causes of concrete cracks,targeted,scientific and reasonable research and the formulation of crack temperature control technical measures will do more with less.In short,choosing a reasonable jump-jump design method in actual engineering,combined with finite element numerical simulation for qualitative analysis,can to a certain extent control concrete cracks,which has certain reference value for actual engineering.