Simulation Of Temperature Field And Research On Maintenance Method Of Large Volume Bridge Pile Cap

In this paper, based on the extra-large bridge mass pile cap of a highway in Liuan, Anhui province, and combined with the basic theory of temperature field, the temperature field distribution was analyzed with the model established by MIDAS/CIVIL software. On this basis, maintenance methods of cushion cap was also studied, the results indicate that effect of temperature control was the best as the top and sides of mass concrete pile caps were fully covered with wet sacks, which would be of great meaning and reference in construction of pile caps, and it shoud be recommended in practical engineering. The main work and conclusions were summarized as follows:1)Relative materials were collected and read, characteristics of mass concrete, research and development outline of the theory of temperature field, and research status of maintenance methods of mass concrete were concluded.2)The basic theory of hydrated heat temperature field was systematic described, related factors of mass concrete and measures to improve the concrete temperature field were summarized.3)Based on engineering practice, appropriate parameters were calculated and selected, the model of pile caps hydration heat temperature field was constructed with MIDAS/CIVIL software, and the influences of cement content and material pattern on temperature field were investigated. It can be concluded that, the higher the cement content in per unit volume concrete, the greater the heat of hydration, and the bigger the temperature difference between the surface and internal of pile cap; the heat-preservation function of bubble template was the best, which can effectively reduce the temperature difference between the surface and internal of pile cap. Besides, the heat-preservation function of wooden template is relatively worse, and the heat-preservation function of steel template is the worst.4)Based on the research of temperature field of mass concrete pile cap, ulteriorly, the temperature fields of concrete pile cap with different maintenance method, i.e. top wet sack coverage maintenance method, top wet sack coverage-sides spray maintenance method, top and sides wet sack full coverage maintenance method, were studied, a comparison was drawn: effect of the control of temperature difference between inside and outside was the greatest with the top and sides wet sack full coverage maintenance method, top wet sack coverage maintenance method followed, and top wet sack coverage-sides spray maintenance method was the worst. Therefore, the top and sides wet sack full coverage maintenance method should be adopted in mass pile caps maintenance.