Curious to hear anyones experience with geotextile wrap for subsoil drains, in particular any studies not funded by the geosynthetic industry on long term performance.

I've seen a couple different combinations: Slotted pipe wrapped in a filter sock embedded in freedraining material. Slotted pipe wrapped in filter sock embedded in free draining material, free draining material wrapped in a geosynthetic as well, slotted pipe embedded in free draining material with no geosynthetic of any kind involved.

I have had seemingly reputable people (20-40 years experience, PHDs etc) advocate for all 3 of these options as being correct at different times in my career.

Personally I'm not convinced that they work long-term. In my experience the biggest advocates for using the filter socks seem to be the people that sell them and people who have gone on week long 'training courses' in vacation-like destinations put on by the manufacturers and come back singing the praises of why we should use as many rolls of material as possible.

Wont the filter sock or the wrap around the geosynthetic just lead to finer particles building up behind it eventually clogging the whole thing and impeding drainage? Curious to see any research, especially by universities or maybe a transport agency that isn't financially captured by the industry that supports these products.