Daryl Dagesse, Geography, Brock University, St. Catharines, ON, CANADA
Soil probes are often used for the collection of “undisturbed” core samples for physical testing or to facilitate the installation of monitoring instrumentation. If the study site is accessible to large mechanical equipment, a variety of methods can be used to both drive the probe into the ground and then extract it. In more remote sites, those not accessible to large equipment (e.g., fields in production, vineyards, orchards), or situations where cost is an issue, manual methods must be employed. Augers or slide hammers are commonly employed to drive probes into the ground. Support from the surrounding soil results in the collection of a relatively undisturbed core within the probe but care must be taken during probe removal to retain the integrity of the sample. For example, upward hammering with the slide hammer used to drive the probe into the ground can shake the soil out of the probe during extraction. Manually pulling the probe from the ground is difficult, particularly when the soil is cohesive, and can lead to bodily injury through over exertion. The construction and operation of a simple and inexpensive device for soil probe extraction is outlined. The device is both lightweight and portable and can be constructed from readily available hardware items with minimal fabrication. The main components include a tripod (which can be re-purposed from surveying equipment as done here, fabricated or purchased) and a screw jack used for leveling construction scaffolding. Fastening the screw jack to the probe via a chain with hooks allows the probe to be smoothly pulled from the hole by simply rotating the screw. Additional force can be applied by having two people turn the jack or mechanical advantage can be gained by extending the handle with a length of pipe.