vertical drain alignment

[Grad1]

Hi,
I know that vertical drains are called so for a reason - they are supposed to be "vertical", but is it preferential to align them at a slight angle from the vertical to catch water in between? I have seen both and wonder which is best. Thanks

 

[BigH]

What kind of vertical drains?

For faster consolidation of fills on soft clay? Then, the answer is vertical is fine - most use square or triangular pattern.

If vertical drain is a row of drains to act as a cut-off say on a slope, then the geometry and such may be such that by angling the drain slightly back into the slope, you can draw the phreatic surface down a bit further back from the slope face - which is usually "good".

So - review your site conditions, what you want to do and then you can make a fine judgment.