黄土丘陵山区坝前淤积土固结渗透试验及其预测模型.

To study the nonlinear permeability characteristics of silted soil in front of dams in the southern mountainous areas of Ningxia, taking the technique of “raising earth-dam from upstream deposited mud” for the reservoirs eliminating danger and reinforcement in loess hilly areas of southern Ningxia as the project background, the consolidation and permeability test was conducted to determine the vertical deformation and permeability coefficient of undisturbed silted soil at depths of 50, 100, and 150 cm under pressures of 25, 50, 100, 200, 400, 800 kPa. Based on the correlation between the permeability coefficient and pore ratio, a double logarithmic nonlinear seepage model was proposed by using pearson correlation and grey correlation analysis, which was suitable for the silted soil in front of earth-dam in this area. Results show that the pearson correlation coefficient and the grey correlation coefficient of pore ratio under 400 kPa consolidation pressure are 0.968 and 0.893, respectively, thus indicating a more significant association between them. Moreover, they surpass the correlation coefficients of other forms of pore ratios. The determination coefficient R² of the fitted seepage model is above 0.93. It not only better reflects the permeability characteristics of silt in front of dam in the southern mountainous area of Ningxia, but also makes up for the shortcomings of insufficient prediction accuracy and complex parameters of the single exponential seepage model. This quantitative model of consolidation-permeability coefficient can provide relative references for the study on large deformation nonlinear drainage consolidation of the silted soil in front of earth-dam. [ABSTRACT FROM AUTHOR]