Geo PM - Slope Stability

[GTScott]

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Compute the factor of safety against failure for the following slope:

Well Drained Sand

2:1

Phi = 32 degrees

Total Unit Weight = 120 pcf

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All of the ways I know to do this (except one) are long and use the method of slices or wedges. There is another way where you get an m and an n factor, but that seems to yield odd results. Does anyone have a good way to work this?

 

[EL Nica PE]

GTScott,

Is that all the infomation they give? Height?under the slope material strengh?

 

[EL Nica PE]

Never mind. This is granular material..

therefore the answer is:

FS=Tan(phi)/Tan (beta)

FS=32/26=1.2

 

[GTScott]

Where did you find that equation? You know who's equation that is? I have not seen one that simple.

 

[EL Nica PE]

I just know that one because I've been doing like hundreds of this slope crap.

But I believe that Das has it.

 

[EL Nica PE]

Here is the equation if given cohesive material...

FS=Tan(phi)/Tan (beta)+Su/(Gamma*H*tan(beta)cos^2(beta))

just in case.

 

[3gorgesdam]

Okay, for c=0, FS = (Pe/Pd)*Tan(Phi)/Tan(Beta). In this case, ut =1.0, therefore Pe = Pd. FS =Tan(Phi)/Tan (Beta)

:whatever:

 

[GTScott]

It is the infinite slope forumula..I get it now. Thanks for the C=0 and Cx=0 forms also.

-GT