Similar FEM For The Thermal Effect Of Cooling Pipes In Mass Concrete Structures

The hydration heat of cement in concrete will cause temperature rising, it can be reduced by the flow of cycle cool water in cooling water pipe, which is buried in advance during construction of mass concrete. This is one of most effective temperature controlling method. In the past, in the simulation of concrete temperature field with cooling water pipe, the cooling effect was considered in the view of average, while the boundary effect was neglected, resulting in low accuracy; substructure method increased the accuracy to some degree, while the work amount was also increased and the pre-process was inconvenient; hybrid element method can calculate the gradient of temperate around pipe more accurately, but it's inconvenient to apply due to the complex expression.The cooling water pipe element is founded in the method studied in this paper. The basic principle is to make similar element division automatically around the pipe, condense similar elements using the relationship between their stiffness matrixes and condense the heat load and radiating boundary, in order to apply ordinary elements and similar elements coordinately.The high-accuracy model of mass concrete temperature field with cooling pipe is provided, and the similar FEM program for pipe cooling in the plane temperature field is worked out. Fixing on the cooling of an infinite cylindrical field, the feasibility and accuracy of cooling pipe element is tested by comparing the result deduced by it and theoretical solution, and the effect of different mesh division to accuracy of result is discussed, which shows that when using cooling pipe element, there is no need to mesh densely around pipe, leading to smaller workload of pre-process and post-process. The effective of radiating capability of concrete to the cooling of pipe is studied and shows it's an effective temperature controlling method to adopt cooling pipe method. Additionally, The practicability of cooling pipe method is tested further by analyzing the effective of cooling pipe in laminar pouring.By introducing the cooling pipe element, many advantages have been brought, for example, the FEM element library is enriched, the amount of pre-process and post process is simplified significantly, and the accuracy is increased, consequently, the contradiction between calculating speed and accuracy is settled.