Vibration induced deformation

[soil1999]

Anyone can guide to a reference on
Estimating settlement of a dry sandy soil foundation (densification) induced by a driving (by vibration) a nearby (10 m far) pile.

Estimating the liquefaction potential of saturated sandy soil as a result of the pile driving/

Can the Peak.Particle.Velocity measurements be useful in this regard (to estimate the above required values.

 

[oldestguy]

Not much help for you, but my limited experience with sand affected by vibration (big air compressors nearby and vibration compaction nearby) is that the more severe problem is not settlement, but migration of the sand out from under a loaded area nearby (footing). No way to estimate it ahead of time, other than it is is ongoing as long as the stuff is vibrated. Of course with migration there is settlement.

 

[Ron]

soil1999....OG is right....lateral migration is often more of an issue than settlement, though direct settlement can occur as well. The resulting damage to the structure is similar in either case.

I would suggest that you get a copy of Dowding's book on construction vibrations. It is good.

"Construction Vibrations" (2nd ed), Charles H. Dowding

I am currently working on a failure investigation for a construction vibration induced problem. Vibrations produced from construction equipment, compaction equipment, pile driving/drilling equipment and others can all contribute. Throw in loose sands and unstable slopes and you have a bunch of problems.

Without regard to trying to predict the resulting settlement, I would certainly recommend monitoring the vibrations both in the ground and on the structure during the pile driving operations. I would also set trigger points based on peak particle velocity or accelerations, depending on the reference you use.

Caltrans has some good info on vibrations, damage and monitoring during construction and from traffic.

"Vibrations of Soil and Foundations" by Richart, Hall and Woods is an excellent source of vibration spectra that can cause damage to structures.

 

[fattdad]

somehow you have to get a fix on the void ratio of the sand and compare that to the critical void ratio. If you are below the critical void ratio, I'm not sure that this is even an issue. If you are above the critical void ratio, then the potential depends on how much greater the existing sand is to the critical void ratio. Seed and Idriss have information on using SPT N-values (normalized), if I recall correctly.

I've never done such a task, however.

f-d

¡papá gordo ain’t no madre flaca!