The generation of water from processing gas or solids is known as liquefaction. Any non-liquid phase occurring as a byproduct of such processing in keeping with the principles of fluid dynamics is also classified as liquefaction. Natural and man made processes can lead to liquefaction. Examples would include converted coal into liquid form as an alternative fuel, air liquefaction separating oxygen, nitrogen and other gasses, etc. Soil liquefaction occurs when saturation results in loss of stability and stiffness. This can be caused by a variety of factors such as stress from earthquakes or other changes in pressure that can make soil take on the characteristics of liquid. Permeation of liquid into space between sediments and soil particulate reduces bonding strength to a point where individual parts of the ground can move freely. This is a particularly important problem that must be remedied for building and infrastructure projects.
The prevention of soil liquefaction can be accomplished by utilizing a perimeter soil/cement wall which can be installed under existing structures. Groundwater is lowered within the perimeter wall which isolates less cohesive soil. This process creates a dry area that is not liquefiable beneath the structure. The soil/cement walls can be installed as block or grid patterns as well as sheer walls. This flexibility of implementation allows for multiple uses such as providing resistance from embankments or almost any other structure where less cohesive foundation soil is an issue. Areas prone to seismic instability particularly need this type of reinforcement. The 1989 Loma Prieta earthquake in the San Francisco Bay Area is a classic example of the dangers of soil liquefaction. A lagoon filled many years before with odd debris and soil under the city’s Marina district gave way to fracturing and horizontal sliding causing massive amounts of property damage.