【摘要】 T构桥墩顶块具有混凝土体积大、应力状态复杂等特点，有效控制混凝土浇筑时的水化热效应是保障全桥工程质量的关键。依托渝黔高铁石梁河特大桥主桥墩顶块混凝土施工，采用数值仿真和现场监测的方法，研究一次性浇筑方案的可行性，对比不同措施对混凝土水化热效应的控制效果，提出墩顶块混凝土浇筑优化方案并应用于实桥施工。提出石梁河大桥墩顶块优化浇筑方案。研究结果表明：原定一次性浇筑方案由于混凝土浇筑体积过大、所采取的降温散热措施很少，导致混凝土水化热温度峰值、最大内表温差和名义拉应力均大幅超出规范限值，不具可行性；分层浇筑、埋设冷却水管是缓解混凝土整体水化热效应的关键措施，调整混凝土入模温度是控制水化热温度峰值和内表温差的重要措施；表面热交换系数与混凝土养护覆盖措施密切相关，对混凝土内表温差有显著影响；所提出的石梁河大桥墩顶块优化浇筑方案为分两层浇筑+底板埋设冷却水管+混凝土入模温度调整至15℃+混凝土表面采用6 mm厚钢板+2 cm厚聚乙烯泡沫覆盖，采用该方案进行现场施工，实测混凝土水化热温度峰值为58℃，最大内表温差22.74℃，最大表面名义拉应力为1.76 MPa，均小于规范限值，说明混凝土水化热效应和开裂风险得到了有效控制。更多还原

【Abstract】 The girder-pier rigid zone of railway T-rigid bridge has the characteristics of large concrete volume and complex stress state, and effectively controlling hydration heat effect during concrete casting is the key to guarantee the project quality of the whole bridge. Taking Shiliang River Bridge of Chongqing-Qianjiang highspeed railway as the engineering background, the method of numerical simulation and in-situ monitoring was adopted, the feasibility of original casting scheme for the bridge was established, the effect of different measures on the hydration heat effect for the concrete was compared, and the optimized casting scheme for the girder-pier rigid zone was put forward.The optimized casting scheme for the girder-pier rigid zone of Shiliang River Bridge was proposed. That was, casting in two layers, embedding cooling water pipes in the bottom slab of concrete,adjusting the temperature of casting concrete to 15 ℃, covering concrete surface with thickness of 6 mm steel plate and thickness of 2 cm polyethylene foam. The results show that the original casting scheme is not feasible due to large amount of concrete casting volume and shortage of cooling measures. During casting process, the peak temperature of hydration heat,the maximum temperature difference between inside and outside of concrete,and the nominal tensile stress on concrete surface all greatly exceed standard limits. Layered casting and embedding cooling pipes are crucial measurements to alleviate the hydration heat effect inside the concrete.Adjusting temperature of casting concrete is an important measurement to control peak temperature of hydration heat and temperature difference between inner and outer surfaces.The convection coefficient of concrete surface is closely related to the insulation and covering measures of concrete, which also has a significant effect on the temperature difference between inside and outside of concrete. The implementation of the optimized scheme is effective in the in-situ monitoring. The peak temperature of hydration heat is 58 ℃, the maximum temperature difference between inner and outer surface is 22.74 ℃, and the maximum surface nominal tensile stress is 1.76MPa, all of which are less than standard limits. It shows that the hydration heat effect and cracking risk of concrete are effectively controlled.更多还原