Design charts for vertical drains considering construction time

This technical note presents design charts for use in determining the requi red drain spacing explicitly using free strain assumption. The influence of time-dependent loading is incorporated in the design charts. The design pr ocedure is also described. When the radius of vertical drain, required degr ee of consolidation, time available, and pertinent geotechnical engineering properties of a soil are given, the charts can be used to design a vertica l drain system without unnecessary trial and error processes.