An analytical solution to the problem of seepage into counterfort drains

Abstract

Recently, J. N. Hutchinson has collected data on the design and performance of trench and counterfort drains. This article presents an analytical solution to one of these cases, that of seepage into counterfort drains which penetrate the full thickness of a layer of soil, down to the impermeable base on which it rests. The soil is assumed to have uniform permeability.The findings of a small study, by Hutchinson, of seepage patterns to such drains, made with the use of finite element methods, are found to be validated by the theoretical approach in this article. This solution also provides a convenient benchmark against which approximate numerical methods can be assessed.Finally, a design chart based on the theory is presented, with examples of its application to the design of counterfort drain installations for slope stabilization.