Active and Passive Soil Pressures 1

[REBSE]

I can find in ASCE Table 3.2-1 Design Lateral Soil Loads to be used for active lateral pressures determined by Unified Soil Classification that I can use as values when I don't have a soils report. However, I cannot find anything for determining a passive pressure to use. Is there a way to convert the Active pressures given to associated passive pressures?

Ryan Erick Broome, S.E., P.E.

 

[oldestguy]

I assume you have some form of soil engineering text book available and there would be a formula for figuring active pressure using a unit weight and angle of friction for both active and passive. Rough guess the density of the soil at 115 #/cf. for granular. Run the formula backwards using the table for granular to get the angle of friction. The compute the passive. Apply a significant safety factor to what ever you come up with. This may help

 

[oldestguy]

Maybe this reads better

 

[oldestguy]

The text by B.K. Hough has a figure that may help. Don't forget to add density for water content, if applicable.

 

[fattdad]

Kp=(1/Ka)

f-d

ípapß gordo ainÆt no madre flaca!

 

[Okiryu]

Looks like those values are based on Rankine theory. You can back calculate the phi using typical soil densities values. Then with that phi you can get the passive.