高掺粉煤灰对特高拱坝封拱后坝体温度回升的影响

The Effect of High Content of Fly Ash in Normal Concrete on Temperature Rise in Super High Dams after Arch Closure

以溪洛渡特高拱坝分布式光纤测温数据为基础,统计分析了封拱后坝体内部混凝土的温度变化规律,认为坝体内部温度回升是胶凝材料水化放热的结果;提出了特高拱坝封拱后坝体内部混凝土中粉煤灰水化放热的计算方法;利用最小二乘法对实测温度回升过程进行拟合,并结合分布式光纤实测温度回升值,计算分析了高掺粉煤灰对溪洛渡特高拱坝封拱后坝体温度回升的影响。研究结果表明,特高拱坝封拱后,导致坝体内部混凝土温度回升的热量几乎全部来自于粉煤灰的水化放热;要有效减小封拱后温度回升对坝体带来的不利影响,其关键是通过对混凝土中粉煤灰掺量的优化调整来控制封拱后的水化放热量。

Based on the temperature data measured by the distributed optical fiber of Xiluodu Super High Arch Dam, the change regulation of the temperature in the dam after Arch Closure is analyzed. It is believed that the temperature rise in the dam comes from the hydration heat release of the cementing material.A calculation method of the heat release of the fly ash in the concrete of the dam body is presented. The least square method is used to fit the measured temperature rise process, and based on the distributed optical fiber measurement temperature, the effect of fly ash on the temperature rise of Xiluodu super high arch dam after its arch closure is quantitatively analyzed. The research results show that, after the arch closure of the super high arch dam, the temperature rise of the concrete in the dam body is almost entirely from the hydration heat of the fly ash. To effectively reduce the adverse effect of temperature rise on the dam body, the key is to control the amount of the fly ash content in concrete by optimizing the adjustment to control the hydration heat of the seal.