Finite Element Inversion Analysis Of Temperature Control Design For Mass Concrete Based On Temperature Monitoring

With the rapid development of China’s economy,various super high-rise buildings,large industrial plants,large-span bridges,etc.continue to emerge,mass concrete structures because of their good load-bearing performance,often important structural components in the above projects.However,due to the poor thermal conductivity of mass concrete structures,the outer surface is relatively good heat dissipation conditions,resulting in the heat loss on the outside of the structure is much greater than the inside,if scientific temperature control design is not adopted,it is easy to form a large temperature difference in the surface,which may lead to temperature cracks in the structure.Relying on the mass concrete foundation project of an industrial plant,this paper carries out the finite element inversion analysis of the temperature control design of mass concrete based on engineering site temperature monitoring through concrete material test,establishment of finite element theoretical model,engineering field test,etc.,and the main work content is as follows:(1)For the mass concrete foundation project of a large industrial plant in China,through the concrete material test and theoretical calculation of the optimal concrete mixing ratio,according to the project experience and specifications,the mass concrete insulation measures suitable for this project are preset.(2)Based on the MIDAS FEA NX finite element analysis software,a finite element model of vertically adjacent two-layer mass concrete is established,and the early development trend of temperature and stress after the pouring of the first poured block is analyzed by using the heat conduction theory,and the maximum temperature and stress of multiple measured points and the corresponding age are obtained.The results show that the temperature control design meets the temperature control standards,which verifies the rationality of the temperature control design.(3)Combined with the structural characteristics and research needs,a temperature monitoring scheme suitable for this project is designed.Through the engineering field test,the construction period temperature data of the first mass concrete block was measured,and a large number of measured temperature data were obtained,revealing the development law of measured temperature in different areas of the structure with age.Combined with the engineering environment,material properties and other factors,the reasons for the error between the finite element results and the measured results are comprehensively analyzed.At the same time,the measured temperature data can also provide an important basis for correcting the finite element model.(4)Based on the measured temperature data on site,the boundary conditions and other parameters of the finite element theoretical model were corrected,and the early stress development curve of each stress characteristic point of the subsequent pouring layer was obtained.The correction results show that there is a certain risk of cracking in the stress characteristic points of the subsequent poured block after the completion of pouring.Using the finite element model to consider the feasibility of construction,the adjustment direction of the subsequent temperature control design is proposed and the safety working conditions are given.Finally,the temperature and development trend were tracked and monitored in the subsequent pouring layer,and the monitoring results showed that the adjusted temperature control measures were well implemented,and no harmful cracks were generated after on-site observation.The results of this paper can provide a reference for the design of temperature control of other mass concrete structures poured by the hopping method.