Computationa Analysis On Thermo-structural Coupling Of Lock Head And Crack

Crack is one of the commonest damage cases in hydraulic construction. Crack exists in most concrete hydraulic construction, being different only in amount and harm grade. Therefore based on full understanding of crack-damage on lock, research on cause of crack and major measures to eliminate crack has significant importance for reducing lock concrete damage, and also guaranteeing normal performance of lock.Taking the head bay of the Changzhou hydro-junction No.1lock of instance, the purpose of the study is to analyze the temperature changes of lock head concrete by using the finite element software to initialize analog computation for concreting of lock head during construction period and considering interaction among hydration heat, air temperature, and layer thickness of construct. Meanwhile, on the premise of results of temperature field, the study analyzes the changes of concrete stress during construction period by using Sequential Coupled-Field Method to initialize the Thermal-Structural Coupling Analysis on concreting of lock head construction. The specific steps are as follows:1、By reading numerous literatures, the study introduces the temperature field, structural internal force and calculation principles, methods and computational process of Thermal-Structural Coupling Analysis.2、Based on practical case, by using finite element method, the study is to build3D-nonlinearity-finite element model to perform model analysis on temperature field of lock head during construction period. The results indicate that the part which is constructed in summer and has thicker layer of construct has higher concrete temperature rise and larger temperature gradient; the results also indicate that places which are more complicated in construction like the concrete of culvert and upper part of repairing silos always have larger temperature gradient.3、By using analytic method and finite element method, the study analyzed the different working conditions of lock head construction. The results indicate that the stress situation of the whole lock head construction is stable. Analytic method is good at simple and convenient computation, while finite element method has more advantages on analyzing characteristic of stress change.4、The Thermal-Structural Coupling Analysis indicates that during the initial stage concreting of lock head construction has less stress; as a result of the characteristic change of concrete construction and impact of inside and outside differences in temperature, the stress is rising; the stress is basically stable after the change of concrete stops.5、During the whole concreting process, the "relative" restraint stress arising from the inside and outside difference in temperature is the main factor to determine the degree of stress when there is no difference of material of concrete and outside restraint situation.6、During the concreting of lock head, the places which are complicated, or have major restraint function, or have large inside and outside differences in temperature, taking the culvert, repairing silos and contact site between baseboard and foundation for instance, have oversize stress more easily. The study suggest proper measures be applied to prevent crack coming into being cause of oversize stress.