Research And Application Of Seamless Construction Technology Of Super-long And Super-thick Mass Concrete

With the rapid development of economy,the scale of engineering construction is getting larger and larger.As one of the main materials for engineering construction,the research on physical and mechanical properties of concrete is relatively mature.With the continuous expansion of foundation volume of large buildings and the increasing amount of concrete poured at one time,the concept of mass concrete arises at the historic moment.In the construction of mass concrete,concrete cracking has become a major problem to be solved urgently.It is a common phenomenon that cracks of different degrees appear in the construction and use process,and it is also a difficult problem that has puzzled engineers and technicians for a long time.Researchers have not stopped studying the cracking problem of mass concrete.There are three main reasons for cracks in mass concrete structures: one is caused by external load;the second is caused by the difference in model design under actual working conditions.the third is that the tensile stress of concrete is caused by temperature factors,shrinkage and expansion,uneven settlement and other reasons in the actual construction process,and cracks will occur when the stress exceeds the tensile strength of concrete itself.In actual projects,cracks mainly caused by deformation account for about 80%,so it is very important to control cracks during construction.This paper aims at practical engineering application and combines with the main construction characteristics of the Yanchang Petroleum Research Center project.First,through the optimization of concrete raw materials and the optimization of mix proportion design,the concrete raw materials and mix proportion which can be better suitable for one-time overall pouring are selected.Then,using the large-scale general finite element analysis software MIDAS/CIVIL2006,selecting reasonable and effectivefinite element calculation models and analysis methods,seamless construction technology research was carried out on the super-long and super-thick mass concrete foundation in the actual project,and the temperature field and stress field changes in the construction process were analyzed.Based on this,24 stress-free barrels were optimally arranged and embedded,and the temperature changes and stress changes in the concrete were monitored in real time.And compared with the results of finite element analysis and analysis,the actual temperature field and stress field distribution,especially the characteristics of stress concentration areas,have been determined,corresponding technologies and maintenance measures have been adopted,accurate and effective dynamic maintenance has been carried out,reasonable allocation of maintenance resources has been realized,and the reliability and effectiveness of the implementation scheme have been ensured.The research results show that the main problems in the seamless construction of mass concrete can be solved by adopting construction technologies such as reasonable material selection and optimization of material mix proportion,effective dynamic maintenance measures in stress concentration areas,and control of crack occurrence and development.The conclusions obtained can be used as a reference for the construction of similar mass concrete.