边界条件对高拱坝真实工作性态的影响研究
发布时间：2019-01-29 20:28
【摘要】：与一般拱坝相比,300m级高拱坝在施工期和运行期对温度边界条件和基础受力边界条件更加敏感。因而,在进行边界条件的计算分析时,采用近似计算或者忽略不计的处理方式已经无法满足实际工程对结构安全的要求。为更加精确化的模拟大坝的真实工作性态,必须对原有的库水温和太阳辐射模拟计算方法进行改进,同时,考虑谷幅收缩等特殊变形对大坝的影响。本文主要研究库水温、太阳辐射和谷幅收缩变形对大坝工作性态的影响。(1)针对溪洛渡等狭长河道型水库在地形、河道、气象条件、径流特征等方面的特殊条件,对原有库水温计算的经验公式法和一维算法进行改进,提出二维横向平均计算方法。改进后的二维算法可模拟水库从蓄水到成库的整个过程,同时使计算精度大大提高。在溪洛渡水库多年的跟踪计算中,与实测值平均误差小于1℃,验证了改进后计算方法的准确性。(2)基于真实山体地形和大坝体形信息,引入太阳辐射热计算模型,真实考虑太阳辐射对拱坝浇筑过程和初期运行的影响,在溪洛渡拱坝施工和运行阶段工作性态跟踪仿真中与实际情况吻合较好,真实的反映了大坝下游面的应力状态。(3)在原有全过程仿真计算中,通过施加两侧位移的方式进行了谷幅收缩变形对大坝结构影响的研究,分析了不同谷幅收缩量值对大坝应力状态的影响。经过多个工况不同收缩量值的对比,得到了大坝横向位移的承受极限。(4)设置多组工况进行对比分析,研究不同边界条件对大坝真实工作性态的影响。分析表明:①采用二维算法得到的水库水温进行仿真计算,其仿真计算结果与一维算法得到的结果相比,两者的应力差异主要集中在水库蓄水阶段,该阶段是大坝温控防裂的关键,应重点关注。②对于下游面朝阳的高坝而言,与不考虑太阳辐射的计算工况相比,最大可造成1MPa的坝面应力增量,且应力分布不均匀,因而太阳辐射热对于坝面开裂的影响不容忽视。③谷幅收缩作用导致坝体整体处于受压状态,但是随着收缩量值的增加,坝体内拉应力逐渐增加,累积收缩100mm时,局部出现较大拉应力,当累积收缩达到120mm时,拱冠梁坝段上游面区域、下游面贴角和左右两岸的坝肩等部位出现区域性拉应力,严重影响大坝结构安全。
[Abstract]:Compared with general arch dams, 300m high arch dams are more sensitive to temperature boundary conditions and foundation stress boundary conditions during construction and operation. Therefore, in the calculation and analysis of boundary conditions, the method of approximate calculation or neglect can no longer meet the requirements of structural safety in practical engineering. In order to more accurately simulate the real working behavior of the dam, the original simulation method of water temperature and solar radiation must be improved. At the same time, the influence of special deformation such as valley amplitude contraction on the dam must be considered. This paper mainly studies the influence of reservoir water temperature, solar radiation and valley amplitude shrinkage deformation on dam workability. (1) in view of the special conditions of Xiluodu long and narrow channel reservoir in topography, river channel, meteorological conditions, runoff characteristics, etc. The empirical formula method and one-dimensional algorithm for calculating the water temperature of the original reservoir are improved, and a two-dimensional transverse average calculation method is proposed. The improved two-dimensional algorithm can simulate the whole process of reservoir from water storage to reservoir formation, and improve the calculation accuracy greatly. In the tracking calculation of Xiluodu Reservoir for many years, the average error with the measured value is less than 1 鈩，
本文编号：2417835
[Abstract]:Compared with general arch dams, 300m high arch dams are more sensitive to temperature boundary conditions and foundation stress boundary conditions during construction and operation. Therefore, in the calculation and analysis of boundary conditions, the method of approximate calculation or neglect can no longer meet the requirements of structural safety in practical engineering. In order to more accurately simulate the real working behavior of the dam, the original simulation method of water temperature and solar radiation must be improved. At the same time, the influence of special deformation such as valley amplitude contraction on the dam must be considered. This paper mainly studies the influence of reservoir water temperature, solar radiation and valley amplitude shrinkage deformation on dam workability. (1) in view of the special conditions of Xiluodu long and narrow channel reservoir in topography, river channel, meteorological conditions, runoff characteristics, etc. The empirical formula method and one-dimensional algorithm for calculating the water temperature of the original reservoir are improved, and a two-dimensional transverse average calculation method is proposed. The improved two-dimensional algorithm can simulate the whole process of reservoir from water storage to reservoir formation, and improve the calculation accuracy greatly. In the tracking calculation of Xiluodu Reservoir for many years, the average error with the measured value is less than 1 鈩，
本文编号：2417835
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