Moisture content is defined as the ratio of the weight of the water to the weight of the solid particles in a soil medium. The moisture content in sands generally lies between 10 percent and 30 percent, while in clay it can range from less than 5 percent to more than 300 percent. The importance of moisture content in a soil mass cannot be understated.

Field-testing of HDD installations was performed at two different locations in order to evaluate the annular space region in both a cohesive and a non-cohesive soil medium.

There has been limited prior work performed in assessing the annular space region created during HDD installations. In one project, researchers performed testing on three 530-foot HDD installations of 12-inch diameter steel pipe to monitor changes in pore pressures before, during and after installation.

New underground infrastructure construction is an important aspect for a developing municipal environment. Installing this new infrastructure using traditional trenching techniques can equate to high social costs, but the use of trenchless methods can enable installation of pipelines and other conduits under sensitive areas, while providing minimal disruption in comparison.