Research On Numerical Simulation And Crack Prevention Technique Of Massive Concrete Structuration Which At Construction Period

It reasearch concrete temperature crack and crack prevention technique of the Yan Shan reservior's massive concrete structuration thought the finite element numercical simulation. It make a deep analysis of gate pier's temperature crack at construction period which take into consideration of differends separte store. bin designs, construction program, cooling and surfate protection measure.Thought the temperature strain analysis on all the concrete piers under the scheme construction condition, it gets the following conclusion:Under The Yan Shan reservior's scheme construcion condition, the possibility of piers which appear thorough crack is very small, the construction program is reasonable. The mainly position of middle piers'crack is at the location of the joint place of high strength concrete. The key of prevating crack is surface protects measure which at the important location and time. The volume of edge piers is big, and the influence of piers inside and outside's difference temperature is big, the possibility of strcture's surface which at lower part is bigger than middle piers. The surface heat preservation and prevation crack of edge piers is needed at all the construction period. After the construction is completed of all the piers, the residual strain of piers'part structure will grow big with the season temperature elevating.Thought the analysis of different conditions of separate bin casting heights, it gets the following conclusion:It can lessen horizontal tensile stress of piers'major structure and reduce the risk of appearing thorough crack thought improving separate bin casting heights. The influence at piers' lower part struction of separate bin casting heights is bigger than at upper, it can reduce horizontal tensile stress of piers'lower part struction effectively. The influence at piers' two sides struction of separate bin casting heights is bigger than at middle, it also can reduce horizontal tensile stress of piers'two sides struction effectively. Separate bin casting heights can reduce tensile stress in the initial pouring stage of piers' struction effectively. Thought the comparative analysis of inside and outside piers' temperture changing, it gets that surface crack is main crack of piers'.Thought the analysis of piers'temperature and stress fields under the cooling water pipe measure at construction period, it gets the following conclusion:It can reduce concrete aquation temperature thought water pipe measure effectively, and it can reduce to about 5 degree of high temperature peak value of piers'. The vaule of temperature between simulated calculation and observation agree well with each other, the change of simulated calculation temperature is relatively accurate, it show that the models and parameters are reasonable, the measure of controling temperature is be carryed out well. The measure of cooling water pipe can reduce temperature stress effectively, it can reduce 20% horizontal tensile stress from population calculation, the possibility harmfulness crack appearing on structure reduces, the effect of temperature measure that control crack is obvious.