Most of the ground we build on can ride out an earthquake, much like a tree, and come through the event without damage. But some types of ground lose all their strength in an earthquake. The ground turns to a fluid, and anything relying on that for support, fails. This is called liquefaction.
And this too can be cured. However the cost normally is great, indeed far greater than would be necessary if we fully understood what was going on in the rare instances where and when liquefaction strikes/erupts.
Recently the unfortunate practice has evolved among engineering businesses of lumping several different types of laboratory specimen behaviours together, and then calling them all liquefaction. This approach likely attracts much more funding than if these un-dramatic, and far less dangerous manifestations of strain, were called by their proper names of cyclic mobility or strain softening.
In our attempt to find the best solution to the real problem of liquefaction proper, and then to design the most efficient way of treating it, we decided this could only be accomplished by ignoring the recent fudging and taking a fresh look at the basic physics involved. Our findings are contained in a small book Liquefiable Materials and their Treatment by Vibro-Draining (ISBN 0-921095-44-9).
Some of our conclusions are that:
* It takes a very unusual hydrogeological environment to deposit a liquefiable soil, so a lot of money could be saved by taking a hard look at the geology of a site before giving it the "when-in-doubt" standard expensive treatment.
* Artificial materials, such as mine wastes and dredged sand-fills, can be dangerous.
* Failure is triggered by the surface waves generated by earthquakes, not the shear waves as is the current assumption in analyses for labelling ground supposedly vulnerable, and then dictating remediation.
* Little energy is required to cure the condition provided it is applied properly.
This understanding resulted in the development of the hardware we call the Phoenix™ Machine.