Geotextile puncture resistance

From the GMA Techline

RE: Geotextile puncture resistance
[I have] a question for you on geotextile puncture resistance. I was looking through your book to refresh my memory on the calculation procedure on geotextile puncture resistance, Section 2.5.4. I saw the scaling factors S2 and S3 and the example calculation reference ASTM D4833, which is no longer recommended for geotextiles by ASTM. They now recommend the CBR puncture test method, D6241 for geotextiles. The puncture values for that test are much higher than those for D4833. How would you recommend adjusting Equation 2.30 and F_allow in this calculation using CBR values?

(Chris | USA)

Reply: The good news is that we have a very nice correlation between pin, pyramid, and CBR puncture responses for geotextiles of different mass per unit areas. The CBR response is five times the pin and the pyramid is two times the pin. Go to:

gt12pp.pdf

The graph is on slide 10 of 13.

The bad news is that for your application there are likely some other scale effects insofar as far as the modification factors S2 and S3. Here you will have to play around with the results and make some estimates.

Hope this helps,

Bob Koerner | GMA Techline