【摘要】：與一般拱壩相比,300m級高拱壩在施工期和運行期對溫度邊界條件和基礎(chǔ)受力邊界條件更加敏感。因而,在進行邊界條件的計算分析時,采用近似計算或者忽略不計的處理方式已經(jīng)無法滿足實際工程對結(jié)構(gòu)安全的要求。為更加精確化的模擬大壩的真實工作性態(tài),必須對原有的庫水溫和太陽輻射模擬計算方法進行改進,同時,考慮谷幅收縮等特殊變形對大壩的影響。本文主要研究庫水溫、太陽輻射和谷幅收縮變形對大壩工作性態(tài)的影響。(1)針對溪洛渡等狹長河道型水庫在地形、河道、氣象條件、徑流特征等方面的特殊條件,對原有庫水溫計算的經(jīng)驗公式法和一維算法進行改進,提出二維橫向平均計算方法。改進后的二維算法可模擬水庫從蓄水到成庫的整個過程,同時使計算精度大大提高。在溪洛渡水庫多年的跟蹤計算中,與實測值平均誤差小于1℃,驗證了改進后計算方法的準確性。(2)基于真實山體地形和大壩體形信息,引入太陽輻射熱計算模型,真實考慮太陽輻射對拱壩澆筑過程和初期運行的影響,在溪洛渡拱壩施工和運行階段工作性態(tài)跟蹤仿真中與實際情況吻合較好,真實的反映了大壩下游面的應(yīng)力狀態(tài)。(3)在原有全過程仿真計算中,通過施加兩側(cè)位移的方式進行了谷幅收縮變形對大壩結(jié)構(gòu)影響的研究,分析了不同谷幅收縮量值對大壩應(yīng)力狀態(tài)的影響。經(jīng)過多個工況不同收縮量值的對比,得到了大壩橫向位移的承受極限。(4)設(shè)置多組工況進行對比分析,研究不同邊界條件對大壩真實工作性態(tài)的影響。分析表明:①采用二維算法得到的水庫水溫進行仿真計算,其仿真計算結(jié)果與一維算法得到的結(jié)果相比,兩者的應(yīng)力差異主要集中在水庫蓄水階段,該階段是大壩溫控防裂的關(guān)鍵,應(yīng)重點關(guān)注。②對于下游面朝陽的高壩而言,與不考慮太陽輻射的計算工況相比,最大可造成1MPa的壩面應(yīng)力增量,且應(yīng)力分布不均勻,因而太陽輻射熱對于壩面開裂的影響不容忽視。③谷幅收縮作用導(dǎo)致壩體整體處于受壓狀態(tài),但是隨著收縮量值的增加,壩體內(nèi)拉應(yīng)力逐漸增加,累積收縮100mm時,局部出現(xiàn)較大拉應(yīng)力,當累積收縮達到120mm時,拱冠梁壩段上游面區(qū)域、下游面貼角和左右兩岸的壩肩等部位出現(xiàn)區(qū)域性拉應(yīng)力,嚴重影響大壩結(jié)構(gòu)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，

本文編號：2417835