testing on vibration transmission

[jimzhang]

Is there a proved field or lab equipment or test that can apply a rod in the soil (like a vibrating drilling) with certain amplitue and frequency? - I am trying to find the right way to transimit vibration waves in soil on large scale.

Thanks!

 

[msucog]

there's different ranges of frequencies that you can aim for but i'm not sure you can pick a particular frequency. what in particular are you trying to do, what kind of materials, depths, distances, etc?

i do have one or two crazy ideas to do what you suggest but more for a specific application (not compaction) and my ideas haven't been built yet.

 

[BigHarvey]

Fied equipment

You can use a vibrator used to drive piles associated to a steel tube or a H pile.You will obtain a vertical amplitude and frequencies around 25 Hz

Alternatively you can use a vibrator used for ground improvement ( a vibroflot which will also be the rod ) which will generate vibrations with a horizontal amplitude and frequencie between 25 an 50 Hz

 

[jimzhang]

Thanks for the replies. It is targeted to transmit the vibration in a 15' radium range, and the depth is also 15'. We are trying to design a vibrate rod with 0.25 inch amplitude and low frequency (<25). Not sure this works or not. Our purpose is not to densify the surrounding soil, but to promote soil movement and water migration.

To answer msucog, the material is mostly sandy and gravelly, now it is desgined as 30'x30'x15'(depth) cell contained by sheet piles. So, what is the crazy idea?

 

[BigHarvey]

It is a typical vibrocompaction job, both methods ( top birator or bottom vibrator ) will work given the depth involved ( 15 ' )but the grid will be smaller with a top vibrator. The only condition to make it work is to have a backfill material with less than 5 % passing #200 sieve.

 

[msucog]

my idea deals more with just transmitting waves through the ground at certain frequencies...not dealing with soil improvement or for what you suggest so there's no need to take up time talking about it here.

my thoughts are in line with bigharvey's. if you're not trying to densify, you might try to utilize multiple large compactors spaces some number of feet apart. not sure if they'd transmit 15' deep. and i'm not sure what frequencies a seismic thumper truck transmit at but that probably be big bucks for that. sorry i can't be of much help.