Using a reduced equivalent diameter for a prefabricated vertical drain to account for smear

Many different formulations for converting a prefabricated vertical drain w ith a rectangular cross section to an equivalent diameter well have been de veloped. in addition to equivalent diameter, engineers must also consider t he impact of smear when designing a system that utilizes prefabricated vert ical drains. An experiment and mathematical modeling were used to study the validity of using a reduced equivalent diameter to account for smear. Math ematical modeling of the four most commonly used equivalent diameter formul ations yielded nearly the same equipotentials. In addition, the equipotenti als calculated for the equivalent diameter wells differed substantially fro m a prefabricated vertical drain modeled with and without smear. This indic ates that equipotentials are not the best means to evaluate equivalent diam eter formulations because the change in shape from a rectangle to a circle impacts the head values to such a degree that the equipotentials will never be similar, regardless of whether smear is included.