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以取自泥石流易发区的182个砾石土土样为基础,进行室内颗分试验,通过分形理论计算各土样的分维值,经计算发现,泥石流源区砾石土以一重分形为主,一重分形的土样占样本总数的88.46%,一重分形土样的分维值介于2.250~2.798之间;以此数据为基础配置土样,通过自制、可控的常水头试验装置进行渗透试验。试验结果表明,渗透系数k与分维值D之间有极显著的相关性,且在干密度为1.8 g/cm3时相关性最好。通过多元回归分析发现,不同密度条件下,k与D之间均有较好的幂函数关系;相同的分维值条件下土样的渗透系数随密度的增大呈减小的趋势,分维值在2.450~2.600之间时,样本的干密度d?与渗透系数k之间的幂函数关系较为明显。试验结果可以为泥石流启动的临界雨量研究提供理论基础,提高已有预报模型的普适性及精度。
According to the fractal theory, the fractal dimension of each soil sample was calculated based on the 182 gravel soil samples taken from the debris flow prone areas. According to the calculation, it was found that the gravelly soil in the debris flow source area was dominated by a single fractal, A fractal soil sample accounted for 88.46% of the total number of samples, fractal dimension of a fractal fractal soil between 2.250 ~ 2.798; based on this data configured soil samples through a self-made, controlled constant head test device penetration test . The experimental results show that there is a very significant correlation between the permeability coefficient k and the fractal dimension D, and the best correlation is found at a dry density of 1.8 g / cm3. Through multiple regression analysis, it is found that there is a good power function relationship between k and D under different density conditions. The permeability coefficient of soil samples decreases with the increase of density under the same fractal dimension value. Fractal dimension When the value is between 2.450 and 2.600, the relationship between the dry density d? Of the sample and the permeability coefficient k is more obvious. The test results can provide a theoretical basis for the study of critical rainfall started by debris flow, and improve the universality and accuracy of the existing prediction models.