塔城水电站筑坝材料的分形维数及其统计特征

Fractal dimension and statistical characteristics of dam material in Tacheng Hydropower Station

粗粒料的颗粒组份大小、形状及其接触方式决定了粗粒料的物理与力学性质,而分形几何在描述上述问题时具有独特优势。以塔城水电站筑坝材料为研究对象,通过建立分形模型,研究粗粒料的分形特性和细料含量对其分形维数的影响,在此基础上建立粗粒土分形维数的统计模型。利用试验成果对该模型进行了参数估计,通过拟合优度检验验证了模型的合理性。分析结果表明,塔城水电站筑坝材料的粒径分布具有较好的分形特性,分形维数介于1.181 9~2.632 3,且服从W e ibu ll概率分布模型。粗粒土中分形维数与细料的含量呈显著正相关,两者的关系可用对数函数描述。上述分析表明,可以用分形维数代替级配曲线来表示堆石料的粒径分布特征,从而使问题得以简化。

The size,shape and contacting formation of coarse-grained component decide the physical and mechanical features of coarse grain,and fractal geometry possesses unique advantages on this problems.Aiming at the dam material of Tacheng Hydropower Station,the fractal model is established to study the fractal characteristics of coarse-grained material and the impact of fines content on fractal dimension.Thus the statistical model of fractal dimension is established.The parameters estimation of the model is conducted by Least-squares method based on the experimental and the model rationality is verified by goodness-of-fit.The results show that the particle size distribution of dam material of Tacheng Hydropower Station possesses good fractal characteristics,and the values are between 1.1819 and 2.6323,which obeys Weibull distribution.The fractal dimension of coarse-grained material is in significant positive correlation with its fines content,and the relationship can be described by logarithmic function.The above analysis demonstrates that the fractal dimension rather than grading curve has better effects in describing the particle size distribution of dam material.