In geology, the term liquefaction is used to describe the process by which soil with a high moisture content starts to behave like a liquid. Liquefaction is caused by an increase in the pressure of the water held in the gaps, or pores, between the soil particles (pore pressure) and is often the result of severe vibration from earthquakes or mine blasting.
Depth
The level of liquefaction caused by mine blasting depends on the quantity of charge and the depth below the surface that the blast takes place. Deep blasts create much more vibration than those at, or near, the surface of the ground.
Pore Pressure
If the existing pore pressure is already very high, it will be magnified by blasting, increasing the likelihood of liquefaction. The local geology and the way in which vibrations are transmitted through the ground are also factors to consider.
Field Studies
Various studies of liquefaction in the field have been conducted using 1 or 2 kg charges buried less than 10 meters below the surface of the ground. Liquefaction was observed within a radius of 20 meters from the blast.
Tags: below surface, mine blasting, pore pressure, surface ground
