ANALYSIS OF FLOW INTO DRAINTILE IN 3-DIMENSIONAL FLOW FIELD

Draintiles (impervious lengths of pipe laid end to end with gaps between adjacent sections to permit water entry) are commonly used in the drainage of agricultural lands and airport runways, and are employed to ensure foundational stability of many structures. The rate of flow into a line of draintiles buried in water-saturated soil depends upon the width and spacing of the gaps between the tiles as well as other parameters. A formula is developed in this paper for the general, non-axisymmetric case to determine the flow rate into a single gap. The differences between the formula developed in this paper and that developed earlier are discussed in terms of their derivation. A numerical example provides details on the essential differences between the two formulae.