Design of retaining structures to BS8002

[JDuk]

As is typically the case with smaller scale retaining structures projects the Site Investigation report rarely contains critical/peak Phi angles for the soils encountered, leaving the engineer to use design values of phi in accordance with correlations between plasticity for cohesive materials, and the BS8002 equation for granular material. I believe I'm correct in saying that a mobilisation factor of 1.2 would be applied against peak phi angle for the ULS design, and peak phi angles used unfactored for SLS design? With this being the case, and with the BS8002 correlations providing values of critical Phi angle only, in the case where design values are not provided within the S.I report, what values of phi should be used within the ULS/SLS calculations?

Thanks

James

 

[Mccoy]

Jduk, what do you mean exactly by mobilization factor, maybe the gamma_phi of Eurocode7 or the gamma_R? Anyway as you well know they vary in the different states beside varying according to the design approach used, I know for example the values adopted in my place.

And what about using phi for a serviceability limit state? Can you make an example? Maybe you enter Mohr Coulomb parameters in FEM softwares to calculate settlements? If you refer to gamma_R SLS calculations don't carry it.