Dynamic Compaction Vibrations 1

[phillyfrank]

I am looking for a way to predict the generated vibration levels in ips from dynamic compaction by weight dropping at various weights, heights, base materials, and distances.

 

[Ron]

Check with Hayward-Baker Foundations. They likely have some info like you are seeking.

 

[BigHarvey]

There is a very good article about vibrations generated vby dynamic compaction in "Revue Française de Géotechnique" N°14 bis march 1981.
It gives for 200 tm to 300 tm energy ( weight x drop height ) the following attenuation formula : V ( in mm/s ) = 340 x d to the power -1.1 with d in meters

 

[marc59]

Phillyfrank,
I have not read the "Revue francaise de geotechnique" paper , but you could find part of your answer in a paper published in the ASCE Journal of Geotechnical Engineering, Vol 110, no6 June 1984 pages 757- 774. The Title is " Ground Response to Dynamic Compaction" by Paul Mayne, John Jones and Jean Dumas.

In this paper, the authors suggest a conservative upper limit for peak particle velocity of:
PPV < 70*(sqrt(W*H)/d)^1.4
Where PPV is the vector sum in mm/sec (1 ips = 25.4 mm/s)
W weight of tamper in tonne (1 tonne = 1000 kg =2204.6 lb)
H drop height in meter (1 meter= 3.2808 feet)
d distance from the drop point in meter
This limit is based on 14 case studies. The authors don't discuss the effect of the type of soil, but based on my own experience vibrations tend to travel easily in clayey material, which has for effect that peak particle velocities tend to be higher. Also, vibration levels tend to be higher as the soils get compacted during the process.
Typical worst case scenario values are 2 ips at 30 feet, 1 ips at 60 feet, and 0.5 ips at 100 feet, which is something you could measure at the end of compaction on a granular material when using a 20 ton tamper falling from about 80 to 100 feet. You don't typically get this with a 15 ton tamper falling from 60 ft.

Hope it can help you!
Marc59

 

[phillyfrank]

Marc59 -- Thanks, on the TerraSystems web site I found the same relationship in English (traditional) units as PPV = 8*(((W*H)^0.5)^1.7)with PPV in ips, W in tons, and H and d in feet. I have e-mailed Paul Mayne at Georgia Tech for more details. If I can't come up with the 1984 article from him, I may ask you for a copy as my files only go back to 1991.