qb value- unit point bearing

[aj_k]

Hi,
Does anyone know how to calculate qb (unit pile base resistance of CPT results) value?
qb = unit point bearing,which is then used to calculate the qc values)
This qb value is used in Belgium practice. It should be calculated by "De Beer"method.
I have searched a lot but i could not get any formulas for calculating the qb value.
I could only find the calculated values, where the formula or calculation is not explained.

https://www.wtcb.be/homepage/downlo...doc=Reference_calculations_De_Beer_method.pdf

The link provided above is the only explanation i could get.
Does anyone know how to calculate these values?

 

[GeoEnvGuy]

Try a newer engineering manual using cpt's

http://www.dot.state.mn.us/research/reports/2018/201832.pdf

 

[aj_k]

Thank you for your reply.
But I am looking for a formula to calculate qb which is unit point bearing by "De Beer" method.
And i need to calculate this qb value by the above method for each soil layer with the provided qc values from a cpt.

 

[geotechguy1]

I don't have any reference specific to the 'De Beer' Method, but in the Canadian foundation Engineering Manual there is a relation for calculating unit base resistance (qt), where qt = kc*qca, where kc is a bearing capacity factor based on soil and pile type and qca is equivalent cone penetration resistance at the pile base (Something to do with averaging qc within a 3/2*pile diameter I believe of the toe - not sure exactly since I've never had to do a calc for these by hand). kc ranges from 0.2-0.55. Section 18.2.3.2.

The same tables can also be found in PK Robertson's CPT Guide 6th edition (

http://www.greggdrilling.com/wp-content/uploads/2017/07/CPT-Guide-6th-Edition-2016.pdf).

Unfortunately neither are the De Beer's method so I can't help you there

 

[aj_k]

Thank you for your help.