Liquefaction of Ground

Liquefaction is more likely to occur in loose to moderately saturated granular soils with poor drainage...There are a number of circumstances than can cause this problem, I am not aware of any test other than examining the soil and checking for adequate drainage....If the soil is uniform in granular size and free of rocks and vegetation this can be a contributing factor...Mitigation is generally done by compacting the soil thru various methods and adding rock columns strategically placed throughout the area of concern....and employing vibro compaction techniques when practical...

Thank you very much. High underground watear level is likely another possibility ?

Yes...such is the case with quicksand....

i apologize. i repeated the gist of your answer.

All soil moves. It is flowing down hill. Either as a mass or loosely on the surface or both.

Because of this movement it could be the dislocation of your pile. And yes any vibration from surrounding structures would accelerate the grounds movement.

It is not so much the frequency that is critical as is the amount of energy.

GA

I suspect that the frequency of an earthquake rumble does have an effect though on what locations of similar terrain will liquefy and which will just sway. I suspect that standing wave effects of node and anti-node resonances are why liquefaction is a very localized effect even though a large area is capable of liquefaction. Remember that for a standing wave to be formed multiple traveling waves must meet to form these anti-nodes where liquefaction occurs. This means that the complex three dimensional terrain shape of the sub-soil bedrock combined with the initial direction and frequency of the shock wave.

In the video with the wheelbarrow in it, he could have just picked up the wheelbarrow a couple of inches and dropped it back down on it's rear supports and gotten the same affect.

I was doing this today when I was mixing up some concrete topping with water. In order to get it to a creamy consistancy, all I had to do was tap the wheelbarrow on the ground a few times and the entire lumpy mixture I had just added water to creamed right up.

I don't think there is a particular 'frequency' needed to cause liquifaction, just and abrupt 'bump' of some sort.

Ok, I didn't make my frequency opinion clear enough. I agree that frequency has nothing to do with if liquefaction will occur at all, energy density does. Frequency and the standing wave effect change the location of peak energy density. Thus only part of this backyard and the rim of the wheel barrow load showed liquefaction because only at these locations were the energy density high enough.

port royal , once a city in jamaca, was built on sand . after an earthquake in 1692, the sand liquified and the city is now 30' beneath the caribbean sea.

i believe the size and shape of the soil particals along with water saturation would be the major factors concerning liquidation, though i'm sure harmonics woulg be a factor. if it viberates, it's going to shift as long as the soil is saturated with water. et al, quick sand.