how to get reasonable result in application of wave equation on pile d

[hgangly]

The numeral solution of wave equation on pile driving is well known today. but when I apply Smith's numerical equations in MS Excel ( measured velocity on top of pile as input), I can't get resonable results, and the caculated force curve is very different with the measured one and is very ugly.

I know these equations have been widely used successfully, but I can not check out what is the problem in my work after I carefully check the equations themself and my code.
I don't know wheather there are some special consideratins there, or any critical concerns to make the equations work properly.

I am very short of resources to get helpful materials, so I hope I can get some helps from some body here.

Thanks

 

[SoilRocks]

I wish I had time to sit down and play around with Smith's original computer solution (1960). Sounds like fun. It's hard to say where the problem might be in that whole spreadsheet without spending a lot of time working on it, as you have. But, if you are sure of all the formulas, then what about your assumptions on input parameters. A wave equation analysis requires input assumptions that can sifnificantly affect the program results. Potention error sources include assumptions on hammer performance, hammer and pile cushion properties, soil resistance distribution, as well as the soil quake and damping characteristics. Since you have measured velocity, I assume you PDA'd a pile, and are using that to test the spreadsheet. To derive all the input parameters from the dynamic measurements (force and velocity), I suggest using more recent references by Goble and Rausche to refine your work. Good luck. Let us all know how it goes. Maybe you'll share your spreadsheet with us all when it works?

 

[LONG1]

Dear friend,
I don't if your result is base on field data or just a numerical analysis. Please remember u have to assume a damping factor in order to fulfil the calculation. If u need details calculation please forward your excel worksheet to me and I wish I can help.

Regards,