Lateral Earth pressure of unyielding wall with slope backfill 1

[Geola]

Earth pressure coefficient of unyielding wall with flat backfill is simply assumed as 1-sin(fi), but I don't know what I should use if the backfill is slope?

 

[fattdad]

1.5 times the appropriate active earth pressure.

f-d

¡papá gordo ain’t no madre flaca!

 

[Geola]

Thanks, Fattdad! Do you have any reference for the value?

 

[Panars]

I have seen ko=(1-sin phi)(1+sin beta) and the reference given as the Danish Code.

 

[fattdad]

If you take Ko=1-sin(phi) and Ka=tan^2(45-phi/2), you get the ratio Ko/Ka ranging from 1.35, to 1.5 to 1.65 for friction angles of 20, 30 and 40 degrees. I just use 1.5.

I used this approach in graduate school and it was well received by Prof. Duncan for an assignment involving at rest earth pressure on a sloping backfill. I have no other reference, except that's what I've done for the last 20 years. No broken walls yet!

f-d

¡papá gordo ain’t no madre flaca!