Crack Prevention And Intelligent Temperature Control System Of Concrete Dam And Its Engineering Application

Crack in mass concrete has been perplexing the engineering community all along,and cracks may influence safety and durability of a dam,increase future maintenance expense,and bring about economic loss and adverse social impact.Temperature control is a main measure for preventing concrete cracking.The high concrete dams to be constructed recently have a few characteristics: larger working face,higher concrete grade,and poorer damming conditions,etc.These characteristics may increase the risk of concrete cracking a nd enhance the difficulty in temperature control and crack prevention,and conventional measures are hard to avoid harmful cracks.The existing temperature control method has the following problems: “not complete,not timely,and not accurate”,of which: 1)“not complete” means that monitoring sections are limited,the monitoring instruments are inadequate,the monitoring frequency is lower,and only limited data on typical sections may be obtained every day.2)“not timely” means that the monitoring system is not high enough in automation level and real-time performance,the data measured daily are limited and cannot be fed back timely.As temperature control is complicated and involves multiple factors such as meteorology,hydrology,material,constructio n,and structure,etc.,an effective solution is hard to give in case a condition changes or a problem happens.3)“Not accurate” means that the in-situ data are generally provided by construction organizations,and the monitoring data must be gathered artificially and post-processed.At the same time,as artificial control mode is adopted,quality of the site staffs may influence the construction quality in a large degree,which may produce major deviations from the design condition and cause “4 main problems” in temperature-controlled construction: larger temperature difference,larger temperature drop,larger temperature gradient,and producing concrete crack finally.Based on existing theories on temperature control,this paper develops an intelligent temperature control system to prevent cracks in concrete dam,and the system has been successfully utilized in a project,which mainly includes:Design of system development database: database design is the base for development of the whole software,and this paper designs and develops the database with working face as the clue to realize high-efficiency management of temperature control information.Design of intelligent temperature control software system: this paper designs database-based intelligent temperature control software system to collect timely,accurate,authentic and systematic monitoring and control information and realizes fine temperature control construction through intelligent temperature monitoring.Engineering application: the system has been utilized in a certain project.The application shows that the system can automatically obtain the temperature information,accurately grasp the real-time evaluation,smart alerts,water control and intelligent decision support,it can improve the management level of large volume concrete construction effectively.