Thread: Pressure on Pavement under Stockpile

1. Pete Guest

pressure on pavement under stockpile

Can anyone tell me how to calculate the pressure distribution on the pavement under a stockpile?

2. Stockpile Pressure Distribution

Not sure how you would go about for a formula of actual pressure distribution. But I calculate worst case condition as follows:

Assume a column of material 1 foot square at the highest point in your pile x that highest point height from ground x the bulk density of the material in cubic feet will give you a number in PSF or pounds per square foot.

Hope this will help.

Gary Blenkhorn

3. Pete Guest
To calculate the worst case is not the problem. I would like to calculate the effect of the "spreading" of forces over a larger area by the product. Like in a silo maximum pressure is at a certain height indepent of filling level.

4. Lets see ..

you have a pile and want to predict the stress level in the pavement under the pile .

you will have I guess a conical pile, with some slope angle like 30 degrees. or so , if there are no fines and you pile has no segregation and no consolidation. the stress field can be calculated , from the internal friction angles.

Formulas for bins, can be used or a simple finite element algorithm in excell can be used . the forces will be spread by the friction in the material. now if you can have segregation and consolidation this forces will change significantly, the worst case approach in this case is sound engeneering practice .

You can see the university of Wollongong book on solids flow , I believe one of the authors is Dr, Arnold. it is a good reference.

There are many publications on slope stability and soil mechanics for civil engeneering

or go back to the basics and use Dr Jenike and Johanson ecuations.

Dr zens also incursionated in this field although his results were not intended for floor loading.

Regards

marco

5. Pete,

If you have a reclaim tunnel, you must consider: the reclaim tunnel configuration (roof, walls, floor), stockpile floor, stockpile material rheology, and soil elasto-plastic response and the withdrawl configrations to reach a maximum stress.

We have performed FEA and DEM analysis on stockpiles. As others have noted by theory and measurements, the classical equations do not predict the true behavior. This is independent of a tunnel. The classical equations do not have the relaxation properties. Hydraulic pressure head is not correct. In some cases. the stress is bimodal in crossection to the pile and peaks off-center.

Sorry, we don't have a simple equation for it.

Lawrence Nordell
Conveyor Dynamics, Inc.
www.conveyor-dynamics.com