Simulation and Analysis of the Temperature Field and the Thermal Stress of an Inverted-Siphon Concrete Structure Based on the Contact Friction Element

Mass concrete structures are prone to suffer temperature destruction during construction and operation because of their own mechanical properties and the role of cement hydration; therefore, the law of temperature field and temperature stress changes is crucial. This paper is based on the heat conduction theory and contact friction element theory under general external load. The heat conduction matrix, node thermal load vector, equivalent stiffness-constraint matrix and equivalent load vector of the contact friction element are each added to the whole heat conduction matrix, thermal load vector and total stiffness matrix, and the total load vector according to the finite element integration rule to establish the thermal-stress calculation model of the contact friction element. Combined with the Qi River inverted siphon project, this paper analyzed the temperature field and temperature stress using the three-dimensional finite element method, considering the changes of concrete thermodynamic parameters with age and the outside air temperature and other conditions, and obtained the distribution and variation in temperature field and temperature stress during the construction of an inverted siphon. The research results are of great significance for temperature control and crack prevention of inverted siphon structures. The thermal-stress calculation model of the contact friction element overcomes the limitations that it is difficult to use the current contact surface model to perform the temperature field simulation and further improves the application of the contact friction element model in the simulation of the temperature field and the temperature stress of mass concrete.