Chloride content of soil

[aj_k]

Hi,
How can we correlate the electrical conductivity (EC) of soil (measured in a CPT test) and Frictional ratio (measured in a CPT test) to calculate the chloride content of soil?
Are there any articles that describe this relation?
I could not find one.
Please help.

 

[GeoEnvGuy]

I work with CPT's cone penetration testing and have not seen electrical conductivity reported or know how they would get that sensor in the cone itself and change the water out with further penetration.

To my knowledge based on Robertson's and Mayne's work I have not heard of CPT's measuring chemical parameters.

 

[Ron]

There is no relationship between the frictional ratio and chloride content. Further, any relationship between electrical conductivity and chloride content would have to be validated since conductivity can be affected by a fair number of parameters that have nothing to do with chlorides.

Run a chemical chloride content test to determine. That's not an expensive nor difficult test.

 

[aj_k]

Thank you for your reply. I do not know much about cpt testing. We do measure the electrical conductivity of soil in a CPTu test. And I have been asked to correlate the EC(electrical conductivity which is measured in mS/cm units) with Rf(frictional ratio), so that we can calculate the chloride content of soil (in mg/liter).

 

[LRJ]

It would take a specialist CPT cone to measure electrical conductivity: an ECPT cone. Are you certain you have these?

I'm also not aware of any correlations like what you describe, so you may have to derive your own site-specific correlation. However, I'm not sure why friction ratio should correlate with either of the other two properties, unless it is a key indicator of different soil units at your site. To some degree I can understand why chloride content and electrical conductivity might be related, but again I'm not aware of any correlations for that either. Who exactly has asked for this and what have they based this on? As noted by others, undertaking soil sampling and chemical testing may be much more straightforward here.

 

[aj_k]

Thank you for your reply.

In Netherlands, they have derived an equation where you can calculate the chloride content from the electrical conductivity that measured in a CPT and the friction ratio.

https://nieuwesluisterneuzen.eu/sit...en nul-situatie zoet-brak-zout grondwater.pdf

In the above link its explained how to calculate chloride content from EC measured (page 5).

https://edepot.wur.nl/7323

In the above link (page 6) explains the equation to calculate formation factor from friction ratio.
The formation factor is used to multiply with EC measured,to get corrected EC.

 

[LRJ]

Dutch is, well... Dutch! to me, so I don't know what those documents say. However, in the first link I can't see how the formation factor comes up in the equation on page 5. In any case, it looks like you've got some correlations there. I would just suggest that you undertake some tests so you can create a site-specific correlation.