French drain 1

[chewbacca]

Hi, I'm just looking the old way (formulas) to design the aggregates grading for a french drain without the geotextiles. I need to manage a seepage in a slope, but the only and unique way is to build the french drain following a secant wall construction method, so the filter fabric cannot be used. The surrounding mass is composed of a mixture of silt and clay in a limestone formation with a lot of small tunnels structure or system due to water piping.

 

[dik]

If you are looking for permanence, I would not delete the non-woven geotextile.

Dik

 

[cvg]

if you do a google search, see the link near the top of this page, you will find that this subject has been discussed many times in the various forums. There are many opinions on the best type of aggregate and on the need or not for fabric.

here is one:
thread193-277245

 

[oldestguy]

You can free download the Navy Design Manual 7.1 Dealing with geotechnical things at:

http://web.mst.edu/~rogersda/umrcourses/ge441/dm7_01.pdf

then go to Figure 4 and 4 continued on page 272 and 273

It has all the basic relations needed for filter design.