高掺粉煤灰常态混凝土与碾压混凝土联合筑坝研究

发布时间：2018-01-05 18:20

本文关键词：高掺粉煤灰常态混凝土与碾压混凝土联合筑坝研究　出处：《清华大学》2015年硕士论文　论文类型：学位论文

【摘要】：向家坝工程高掺粉煤灰常态混凝土与碾压混凝土联合筑坝的实践,突破了原有筑坝理念。目前向家坝大坝已按期蓄水发电,各项监测数据正常。快速施工是碾压混凝土所具有的突出优点,未来混凝土重力坝在施工阶段采用碾压混凝土和常态混凝土联合筑坝将成为缓解进度压力的有效手段,同时高掺粉煤灰的常态混凝土应用也是今后水电建设发展的方向。因此,需要更好的分析高掺粉煤灰常态混凝土与碾压混凝土热力学性能,更真实的了解大坝工作性态,并归纳总结联合筑坝关键技术。本文首先利用温度计、无应力计、测缝计等各种监测仪器的长龄期实测数据,分析向家坝的坝区气温以及纵、横缝开度等信息,反演大坝混凝土的线膨胀系数,为之后的模型仿真计算提供条件参数。之后进行了高掺粉煤灰常态混凝土与碾压混凝土绝热温升与主要力学性能试验研究,用新发明专利技术试验反演绝热温升,对比高掺粉煤灰混凝土与碾压混凝土的绝热温升曲线,可以得到常态混凝土的前期温升快,碾压混凝土后期温升潜力大。以向家坝大坝实施配合比为基础,适当调整配合比参数,进行常态混凝土多种粉煤灰掺量(20%、30%、40%)试验,包括绝热温升、抗压强度、劈拉强度、弹性模量试验,分析得出随着粉煤灰掺量增大,四项热力学性能指标均随之减小。以试验所得绝热温升参数为基础,通过仿真计算,反演高掺粉煤灰常态混凝土与碾压混凝土的绝热温升参数,得到二者的绝热温升曲线。同样可以得到常态混凝土的前期温升快,碾压混凝土后期温升潜力大的结论。考虑施工季节、浇筑温度、分层厚度、温控措施以及蓄水情况,对泄4坝段施工期和运行期的温度场、应力场进行仿真计算。结果表明坝体冷却通水效果良好,温度场、应力场均符合安全要求。最后,以泄4作为典型坝段,调整泄4坝段甲乙块碾压混凝土的力学参数,计算坝段变形和应力的变化,探索常态、碾压两种混凝土变形应力性能的敏感性。
[Abstract]:The practice of the combination of high fly ash concrete and roller compacted concrete in Xiangjiaba project breaks through the original idea of dam construction. At present Xiangjiaba dam has been storing water and generating electricity on schedule. The monitoring data are normal and the rapid construction is the outstanding advantage of RCC. In the future, the use of RCC and normal concrete in the construction stage of concrete gravity dam will become an effective means to alleviate the progress pressure. At the same time, the application of normal concrete with high fly ash is also the development direction of hydropower construction in the future. Therefore, it is necessary to better analyze the thermodynamic properties of normal concrete and roller compacted concrete with high fly ash. More true understanding of dam working behavior, and summed up the key technologies of combined dam building. Firstly, this paper use thermometer, stress meter, jointmeter and other monitoring instruments of the long-term measured data. The temperature and the opening of longitudinal and transverse joints in Xiangjiaba dam area are analyzed and the linear expansion coefficient of concrete is retrieved. After that, the adiabatic temperature rise and the main mechanical properties of high fly ash concrete and RCC are studied. Comparing the adiabatic temperature rise curves of high fly ash concrete and roller compacted concrete, the temperature rise of normal concrete can be obtained quickly. The temperature rise potential of RCC in the later stage is great. Based on the mix ratio of Xiangjiaba dam and adjusting the mix ratio parameters properly, the test is carried out with the addition of multiple fly ash in normal concrete. Including adiabatic temperature rise, compressive strength, splitting tensile strength, elastic modulus test, the analysis shows that with the increase of fly ash content, the four thermodynamic performance indexes are all reduced, based on the adiabatic temperature rise parameters obtained from the test. Through simulation calculation, the adiabatic temperature rise parameters of high fly ash concrete and roller compacted concrete are inversed, and the adiabatic temperature rise curves of them are obtained, and the early stage temperature rise of normal concrete can also be obtained. Considering the construction season, pouring temperature, layering thickness, temperature control measures and water storage, the temperature field in construction period and operation period of dam section 4 is considered. The results show that the cooling water flow effect of dam body is good, and the temperature field and stress field all meet the safety requirements. Finally, the typical dam section is Xie4. The mechanical parameters of roller compacted concrete (RCC) in No.4 dam segment are adjusted, the deformation and stress changes of dam segment are calculated, and the sensitivity of deformation stress properties of normal and roller compacted concrete is explored.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TV544

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