الفهرس 
Chapter (1): INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This research was in hared with the objective of increasing the efficiency of draining a heavy clay layer of low hydraulic conductivity over lying an impermeable layer by means of a combined system of tile and mole drains- Amole drain is an unlined underground drainage channel, formed by pulling a solid object, usually a solid cylinder with a wedgeshaped point at the end, through the soil at the proper slope and depth, without digging a trench - The complex potential, the stream function, and the velocity potential are provided using the theory of complex functions and the theory of images. New discharge formulas for both tile and mole drains were established. Formulas for calculating the velocity components at any point are provided.
A computer program was developed with the aid of (maple 9) software to solve the governing equations to calculate the discharge per unit length for both mole and tile drains. Effects of several parameters such as, spacing between tile drains, mole drains diameter, height of water above tile drains, the top clay cap thickness below tiles center, spacing between mole drains and the vertical distance between tile drains and mole drains are investigated mathematically.
Graphs are provided to illustrate the relation between the discharge per unit
length of tile and mole drain and each of the involved parameters. From
the above relations, it was clear that:
• The best economical achievement occurred when a small vertical
distance between the tile and mole drain was used.
• The mole drain is very efficient for enhancing the tile drain
efficiency in case of high water head and small clay cap thickness.