Seepage polluted or contaminated water that may

Seepage flow is the most important consideration and it has been well recognized in geotechnical engineering practice (dams, slopes, landslides, underground spaces, etc.) . Seepage flow through soils, rocks and geotechnical structures has a great influence on the deformation and stability of soils, rocks and geotechnical structures. Seepage control is critical technological issue in engineering practices for maintaining the stability and safety of the e ngineering works.
Understanding the physical mechanisms and their corresponding numerical modeling approaches of engineering measures for seepage control is obviously of paramount importance for safety assessment, optimization design, construction and operation of a seepage control system.
A large number of engineering measures have been widely taken for seepage control in geotechnical and geoenvironmental engineering practices, and they can generally be classified into four categories. The first category involves in the construction of an impervious zone with low permeability and high critical hydraulic gradient to limit the quantity of seepage flow, reduce the pore water pressure, and preserve the geometrical integrity of the impervious system, such as clay core, asphalt-concrete core, concrete face slab or impervious blanket in embankments, grouting curtain in rock foundations, etc? The second category employs filter and drain zones in soil/rock foundations, underground caverns and concrete/soil dams to reduce pore water pressure (especially the uplift pressure), collect and remove seepage water, and prevent soils from seepage failure, such as drainage holes, wells, tunnels, prisms or horizontal drainage blankets. The third category is associated with the operation and management of the reservoir, such as the control of the effect of water level fluctuation on groundwater movement. The last one is to improve, by various groundwater remediation techniques, the quality of polluted or contaminated water that may cause hazards to environments and society.
The movement of groundwater in fractured porous media is governed by the mass and the momentum conservation laws of water, with the latter commonly being represented by the well-known Darcy’s law, and subjected to the constraints of initial conditions, boundary conditions, material properties and computational requirements when numerical modeling is needed. Theoretically, the seepage flow process will be altered or controlled by changing, adding or removing the storage terms in the governing equation, changes of the initial and boundary conditions, or changes of the hydraulic properties as the process evolves. Thus, it is essential to understand the physical mechanisms of various engineering measures for seepage control by linking the control effects with corresponding components in the mathematical model of seepage flow, i.e. governing equation together with initial and boundary conditions and computational parameters. By doing so, performance assessment and optimization design of the seepage control structures can be established on a more rigorous mathematical basis and a sounder scientific foundation.