Active pressure on rigid wall near rock face

[courtpara]

I have a situation where a cantilever retaining wall will retain a roadway on rock slope. The retaining wall will be supported on existing fill of good quality on slope. The heel is touching the rock slope. The slope is 3H:1V away from the wall. Since sheeting will be used during construction, part of the existing roadway fill behind heel will remain in place (friction angle 30 degree, moist unit weight 120 pcf) and the portion over the heal will be backfilled with granular materials (friction angle 34 degree, moist unit weight 120 pcf. Which friction angle should be used in active pressure calculation? Any help is greatly appreciated.

 

[hokie66]

I would use the most conservative, i.e. 30 degrees.