Multi-physics Coupling Analysis of Clayey Core Wall of High Earth-Rockfill Dam by Yongkang Wu

Author:Yongkang Wu
Language: eng
Format: epub, pdf
Publisher: Springer Singapore, Singapore

(4.41)

Finally, the continuity equation of pore water in unsaturated seepage-consolidation analysis is derived as follows:

(4.42)

where

By substituting Darcy’s law into Eq. (4.42), the continuity equation of pore water can be further expressed as follows:

(4.43)

The expression of Eq. (4.43) can also be derived using the sign convention in soil mechanics. However, and Ss need to be expressed as

4.5 Coupling Analysis Method for Unsaturated Consolidation

The core wall is a key part of the earth-rockfill dam. The stress-deformation and seepage behaviors of the core material in high earth-rockfill dams are significantly different from those of low dams. In high dams, the core material bears extremely complex changes in seepage and stress-deformation state in the process of construction, impounding, and operation.

Due to the complexity of the construction conditions and the limitations of the test conditions and numerical methods, the existing numerical simulation analysis methods cannot fully reflect the actual states of stress, deformation, and pore-water pressure of the dam materials. In addition, there are complex interactions between stress-deformation field, the physical-state field and the seepage field in the dam body. In particular, for the problems of saturated-unsaturated seepage and consolidation analysis in high earth-rock dams, the effect of multi-physics coupling should not be neglected. The current theories and methods still hardly reflect these characteristics. For the consolidation problems with high stress and large deformations, ignoring the coupling effects will cause significant errors in the numerical analysis.

The complex interactions between the stress field, the deformation field, the physical-state (including the density, the degree of saturation, the mesostructure, etc.) field, and seepage field in the core wall of high earth-rockfill dams can be illustrated by Fig. 4.2. The permeability of soil directly affects the distribution of the seepage field and plays a decisive role in the evolution of the pore-water pressure in the core wall. And the variations in the seepage field will change the stress and deformation state and physical state of the soil. There are also interactions between the stress-strain state and the physical state of soil; the physical state (e.g., the degree of saturation) will affect the matrix suction in the soil and thus affects the effective stress; soil deformations (e.g., compression) will induce variations in the physical state of soil. And both the stress-deformation state and the physical state have significant influences on the permeability of soil.

Fig. 4.2Diagram of the multi-physics coupling relationship in the core wall of high earth-rock dams

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