Hello everybory

I'm trying to model underground pipeline not before have reading Peng's papers "Stress Analysis methods for underground pipe lines", which according to Caesar II chapter 11 is the basis for the caesar II soil restraint modeling algorithm.

Also by reading chapter 11 on page 10, it is supossed to be an equation for Transverse Ultimate Load (Ftr), but there is nothing indicated, at least in the one I am looking at.
May this Ftr equation be represented by the equation (10) of Peng's Paper?:i.e. U=0.5g(H+D)²tan²(45+Φ/2), where g is the density of backfill soil, H+D is the depth until the trench bottom and Φ is the angle of internal friction.

Now, can anybody, that had read both of the Peng's paper, please tell me if the equation (8) is just for the unrestrained portion? or how this equation should be understood?

And why in Part 2 "Soil pipe interaction" in sample calculations, the end force Q is calculated twice by two different equations? if according to the mathematical development there is just one equation for Q, I mean equation (16).

I hope anybody could help me to clear my doubts

Thnak you very much in advanced

Hello

I really would like somebody to give any response please

Thank you

Yes, the equation on page 11-10 of the CAESAR II User Guide was developed from Peng's equation 10. We added "OCM" as a convenience to adjust this value.

Peng's equation (8) calculates the free expansion rate from both thermal and pressure components. That's unrestrained growth. Throw in EA and you get equation (6) which is the potential anchor force supplied by axial soil friction or a true anchor. That's fully restrained load.

Q is the end force and is a function of the soil bearing load and the axial, friction load.

Sor,
Based on my experience I would advise you use the ASCE soil modelling method that has recently been added to CaesarII. I found it much easier to understand and implement.

M Aminu