Application Of Inverse Thermal Analysis For The Thermal Properties Of Massive Concrete Structures

With the improvement of the overall quality and modernization of the city,the demand for concrete construction technology has become higher and higher.Large quantities of massive concrete projects can be seen everywhere.What follows is a critical technical problem that arises in the construction of mass concrete-the control of temperature cracks.Numerical simulation methods such as finite element analysis are often used to predict cracks of massive concrete structures,however the accuracy of the analysis often depends on various thermal properties’ values.These thermal properties are based on the materials themselves under actual conditions and it is very difficult to obtain high reliability values.There are currently no fixed test methods although they can also be obtained from laboratory tests and the laboratory structure is often very different from the actual situation.First of all,due to large amount of concrete poured into the massive concrete structures and the internal hydration heat energy is not easily dissipated,a large amount of concrete will cause thermal cracks.If they are not controlled,it will gradually develop into a through-crack,which may affect the safety of the structure in severe cases.The finite element method is usually used directly for direct thermal analysis using empirical values or laboratory measured values.However,it has been found through the study that there is a deviation between thermal analysis performed using general values and the actual measured values.Secondly,the swarm intelligence algorithm has a good performance in the optimization problem.This dissertation chooses a particle swarm optimization algorithm and an artificial bee colony algorithm,both of which have perfect theory and operation.The two algorithms are used to optimize the thermal properties’ value.Finally,the dissertation integrates the above two swarm intelligence algorithms to identify the thermal properties’ value by loading the measured temperature into the thermal analysis in order to solve the problem of deviation between temperature analysis and actual conditions under general values,The value obtained in this case will be a value closer to the actual situation of the project and will also build a good foundation for future stress analysis and crack estimation.The engineering example verified that there is indeed a large deviation between the results of the temperature analysis using the general thermal properties values and the actual measurement temperature,and the thermal properties values identified by the method are reversed and reloaded into the temperature analysis.The performance is good.Compared with the general value,it is closer to the actual situation of the project.Therefore,this method can be used to optimize the thermal analysis of the structure in the massive concrete construction stage and provide practical reference for the prevention and control of cracks.