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针对大跨连续刚构桥承台大体积混凝土结构施工过程中的水化热问题,利用有限元分析软件进行了模拟分析,并对承台施工过程中的水化热温度进行了细致的监测。经过分析,得出有限元的模拟计算结果与现场监测的温度变化趋势一致,与承台内部的最高温度相差约9%。计算模型中对流边界条件的选取、承台浇筑的分层方法、冷却管水流的模拟等与实际情况的差异是影响模拟精度的主要因素。通过不同测点布置形式可以得到混凝土内部的温度梯度分布,远离承台中心位置温度梯度较大,应采取良好的保温保湿措施防止温差下混凝土的开裂。施工过程采用计算、监测以及现场养护等综合技术措施,较好地避免了大体积承台混凝土施工期间温度裂缝的出现,确保了承台的施工质量。
Aiming at the problem of hydration heat in the process of construction of large-span continuous rigid frame bridge cap, the finite element analysis software was used to simulate and analyze the hydration heat temperature in the process of cap-bearing platform construction. After analysis, it is concluded that the simulation results of finite element are consistent with the trend of on-site temperature monitoring, which is about 9% of the maximum temperature inside the cap. The main factors affecting the accuracy of simulation are the selection of convection boundary conditions, the stratification of pouring platform, the simulation of cooling pipe flow, and the actual situation in the calculation model. Through the arrangement of different measuring points, the temperature gradient distribution inside the concrete can be obtained, and the temperature gradient is far away from the center of the cap. Good thermal insulation and moisture retention measures should be taken to prevent cracking of the concrete under temperature difference. The construction process adopts the comprehensive technical measures such as calculation, monitoring and site maintenance to better avoid the occurrence of temperature cracks during the construction of large-size pile cap concrete and ensure the construction quality of cap.