Research On Temperature Effect And Construction Method Of Super Long Mass Concrete

With the increasing complexity of building structure forms,super long mass concrete structures are being widely used in various building structures.At present,there have been many studies on the temperature and stress control of mass concrete at home and abroad,but the size effect of super long mass concrete and the selection of construction methods under specific environment and conditions still need to be further explored:At present,the structural monitoring technology for the temperature and strain change of mass concrete has been very mature.However,there is no unified principle for the determination of concrete setting time and the selection of monitoring deformation zero point in practical engineering,so it is necessary to carry out relevant theoretical and practical research.Based on the analysis of strain monitoring mechanism and the actual monitoring data of super long mass concrete floor of a project,this paper puts forward a judgment method of setting time and realizes structural safety evaluation;Through finite element analysis,the temperature field and temperature stress development of one-time pouring and sequence pouring are simulated,and their advantages and disadvantages are compared to provide suggestions for the construction of similar projects.1.A method for judging the final setting time of mass concrete based on strain monitoring and the selection criterion of effective deformation monitoring starting point are proposed,and then the structural safety state is evaluated.Firstly,the monitoring mechanism of strain response is analyzed,and it is concluded that there should be a linear negative correlation between the early strain and temperature of the structure.Further,the theoretical and correlation analysis of the early data of self pouring construction is carried out,the practical significance of each stage is expounded,and the final setting time is further judged;The results show that the development process of monitoring strain response can reflect the setting degree of concrete,and the conclusions are basically consistent with the conclusions based on the rapid growth of temperature,which provides an important reference value for the selection of deformation zero point of structural monitoring and subsequent crack analysis.2.Use ANSYS finite element analysis software to simulate the temperature field and temperature stress of one-time pouring construction of super long mass concrete structure,and compare with the measured data to verify the feasibility of finite element analysis.At the same time,conduct parametric analysis to explore the influence size and range of pouring block length on temperature stress under specific construction environment and conditions,It can be seen that there is a nonlinear relationship between length and stress.After 60 m,its influence on stress can be ignored.3.Use ANSYS finite element analysis software to simulate the temperature field and temperature stress of sequence pouring construction of super long mass concrete structure,and compare it with the results of one-time pouring scheme,so as to explore the advantages and disadvantages of different construction methods under specific construction conditions.The results show that the two construction methods will not cause excessive temperature stress and are safer in summer.During the construction of similar projects,the factors such as the construction season,construction period requirements,structural function and integrity requirements shall be combined,and the appropriate construction method shall be selected through the preliminary finite element analysis,so as to achieve the purpose of structural safety and shorten the construction period.