[Univ of Cambridge] [Dept of Engineering]


SEEPAGE is a program designed for second year undergraduates who will have attended one term of lectures on soil mechanics.

The aim is to provide the user with an interactive capability for producing flownets for the following categories of commonly occuring geotechnical problems:

  1. flow beneath a cantilever retaining wall

  2. flow through an earth dam

  3. flow beneath a concrete dam with cut-off

Inputs and Outputs

A student can choose one of the above categories to investigate and then change the geometry of the boundaries that define it. He can also change the potential of the upstream and downstream boundaries of each category and enter a permeability for the soil. Output is in the form of a flownet with ten potential intervals, the water pressure at any selected point can then be output directly. Flow quantities are automatically displayed, consistent with input information concerning the permeability, which is taken to be constant and isotropic throughout the flow region.

A finite element mesh is generated automatically to cover the area inside the boundaries. Laplace's equation is then solved both for the potential and stream functions using the finite element technique (Galerkin) as described by Brebbia and Ferranti. The boundary conditions for the stream function are obtained from the solution of the potential function so that curvelinear squares are produced.

A simple contouring routine is used to obtain the lines of constant potential and flow.

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Updated on 12th December, 1997