"Toy" wrote in message ...

"Marcus Fox" wrote in

message ...

I am trying to calculate a formula to determine approximately how much

earth/material I would need to create a "pile" - for want of a better

word -

of a given height I could use just earth, but I could also have a pile of

rocks covered by earth.

The pile will be approximately cone shaped, and I know the formula to

calculate the volume of a cone. 1/3 pi r2 (base radius) x height. However,

since the soil will spread out and the base gets wider as the height

increases, I need to know to what degree this will happen, for example

what

is the smallest slope in degrees where the pile will remain stable? 45? If

this is the case then the radius of the base will be the same as the

height.

Thanks for any input.

Marcus

first it depends on the material.

sand would have a shallower base angle for instance.

if you have the same amount of material and it starts to spread out, without

adding more material, the volume remains the same.

or am I missing something here.
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http://grapevine.abe.msstate.edu/~ft.../vol/cone.html
put in your sizes and hey presto, volume....