The use of drilled foundations is a growing technology nationwide that provides a reliable long lasting solution. More recently, a trend has developed among architects, engineers and owners pushing for larger diameter and longer drilled shafts to be installed. In lieu of this trend, we have also seen an increase in slurry-displaced shafts. Whether you choose a mineral slurry or a synthetic slurry for your application, hydrostatic head pressure is a key element in maintaining shaft stability. Hydrostatic head is defined as “the pressure at a given point in a liquid measured in terms of the vertical height of a column of the liquid needed to produce the same pressure.” In other words hydrostatic head pressure is the pressure slurry exerts to combat the natural formation pressure of the earth and groundwater.
Pressures are forces and are prevalent in our everyday lives, even though we may not always recognize them. In fact, atmospheric pressure is always being exerted on our bodies and everything around us. The same holds true each time we drill a shaft. There are many different pressures involved and, in order to be successful, we must balance and/or counteract the pressures at hand with an equal or greater force.