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The hydraulic resistance of river ice jams consists of the resistance due to the seepage flow through the jam and the resistance due to the shear stress on the undersurface of the jam. Existing empirical formulations attributed the entire jam resistance to the undersurface resistance of the jam, but relate the jam resistance to jam thickness with little theoretical basis. Based on the analysis of the seepage flow resistance and the flow resistance of the undersurface of the jam, it is shown that the resistance due to the seepage flow is a dominating part of the jam resistance, except for the portion of the jam where the thickness is very thin. This analysis also showed that the total jam resistance can be approximated by a linear function of the jam thickness or the ratio of jam thickness to the flow depth under the jam.

The equivalent permeability tensor is essential to the application of the equivalent porous media model in the numerical seepage simulation for fractured rock masses. In this paper, a revised solution of the equivalent permeability tensor is proposed to represent the influence of the fracture connectivity in discontinuous fractures. A correction coefficient is involved to reflect the complex seepage flow type through the rock bridge. This correction coefficient is back analyzed from single-hole packer tests, based on the Artificial Neural Network (ANN) back analysis and the Finite Element Method (FEM) seepage simulation. The limitation of this back analysis algorithm is that the number of single-hole packer tests should be equal or greater than the number of fracture sets, and three is the maximum number of the fracture sets. The proposed solution and the back analysis algorithm are applied in the permeability measurement and the seepage simulation for the Xiaowan arch dam foundation.

On the basis of the generalized physical model of the riverbank, the experiments were conducted to study the mechanisms of riverbank failure under the coupling effect of seepage flow and river flow. The experimental setup was specially designed, as well as test point location, parameters and procedures, and the main influencing factors were analyzed affecting riverbank failure based on the failure types, the variations of pore water pressure and soil displacement. The results indicated that the coupling effect has different influences on the bank failure in three aspects: the failure type, the process and the extent. In addition, the river flow played a more important role than the seepage flow in the coupling effect on the bank failure.

The movement of water flow in unsaturated fractured rock was investigated with the sandstone sample through experimental research and numerical simulation. The experimental results show that the arriving time of wetting front is delayed by the fracture, resulting in the increase of water saturation in the domain on the upstream side of the fracture, which will locally enhance water flow through the matrix. The numerical simulation with the finite volume method captures effectively these characteristics. The comparison between simulated and observed travel time and arriving time of wetting front shows that their difference are very small and the simulated results are in agreement with the observed results, which implies calibrated parameters are reliable and effective. Then according to the calibrated parameters, fractured models were established to examine how the change of large fractured aperture would affect the arriving time of wetting fronts, pressure heads and water saturation on the upstream and downstream sides of fracture.

A numerical model is proposed to simulate the unsteady seepage flow through dam, with both saturation and water head as variables to describe the seepage domain. Experiments of seepage flow through dam with unsteady conditions were conducted in laboratory to verify the reliability and the accuracy of the numerical model. The performance of the model is also assessed by comparing with analytical solutions. The examples show that the accuracy and the reliability of the model are adequate to handle seepage flow problems with complex conditions. It is also demonstrated that the method of determining the seepage surface through the saturation description is natural, logical and practical in actual applications. The method provides a relatively simple computing scheme, as compared with traditional methods.