LIQUEFACTION

Well Now I will stop a little talking about geology and seismology, because I want to talk about a topic that has to do more with engineering and tecnique, I will talk abuot liquefaction in soils, because is a very importat them for geotechnical and structural engineers.

During earth quakes the movement on the ground can make lose stiffness in the soil, and cause to collapse structures of buildings, soil slides or damages in pipes underground, and this is because the liquefaction of the soil, and is associated to non-cohesive soils as the sands and silty sands with the water table enough neared to surface.

The terms liquefaction includes all phenomena where is present an excessive deformation or movements as a result of repetitive transient disturbances in saturated soils and low cohesive.

During the large magnitude of destructive affects in the Nigata, Japan earthquake in 1964 engineers understood that was very important to give all attention to this phenomenon. Since and then there have been significant advances to understand this phenomena and this effects analyzing and evaluating the potential of liquefaction of a soil and developing new technologies to to mitigate earthquakes destroying effects.

The knowledge about process and its effects has been based in three different principles.

1. Observation; during and after an earthquake.
2. Lab experiments an satured soil samples, and in structural models.
3. Theory studies.

Some of the liquefaction effects are catastrophic, as the collapse of large slopes or dams, collapse of bridges, walls and buildings. Other effects are less dangerous as large deformation on the ground surface, or floods in big areas.