Direct Push Tooling is used to perform soil, soil gas, and groundwater sampling. It is also used for soil remediation, and geotechnical sampling and testing. Many AMS PowerProbe direct push drill rigs also have hollowstem augering capabilities.
Direct Push Drilling Technology allows for a wide variety of direct push tooling and instrumentation to be advanced into a subsurface lithology using the static weight of the rig, hydraulic down pressure, and rapid hydraulic hammering.
Compared to conventional drilling, direct push drilling is less labor intensive, offers quicker setup time, and generates less drill cuttings. Direct push tooling is also easier to decontaminate and maintain.
Geoprobe® pioneered Direct Push Subsurface Sampling Technology in 1987. A direct push machine “pushes” tools and sensors into the ground without the use of drilling to remove soil to make a path for the tool.
Geoprobe® direct push machines rely on a relatively small amount of static (vehicle) weight combined with percussion as the energy for advancing a tool string. Direct push tools do not remove cuttings from the probe hole but depend on compression of soil or rearrangement of soil particles to permit advancement for the tool string.
Direct push tools are advanced as far as possible using only the static weight of the carrier vehicle. Percussion is applied as required when probing through sands, gravels, hard pans, high friction clays, tills, fill materials, and surface frost.
Direct push technology facilitates better vertical profiling capabilities for generating three dimensional profiles of a site by providing undisturbed soil cores that offer a more accurate depiction of sub-surface properties. DPP uses both macro core and dual tube sampling systems to obtain continuous soil cores or discrete soil samples from specified depths. The Macro-Core MC5 soil sampler provides some of the most coherent, efficient and consistent samples and is suited to collecting large volumes of soil cores at shallow depths.
For most projects, the dual tube system (DT-32) is more effective as it allows continuous, discrete soil sampling from a cased probe hole. This eliminates the threat of material falling into the borehole and provides maximum sample integrity as well as an accurate bore log. Sample integrity is better than obtained by hollow stem augers and direct push technology also enables such projects to be completed faster and more cost effectively.
DT-32 soil samples are contained within a 50mm diameter clear liner that can be sealed for subsequent offsite analysis or half the casing can be removed for on-site sampling and logging.
Dual Tube Sampling Dual tube sampling uses two sets of probe rods to collect continuous soil cores from ground level to a pre-defined depth. One set of rods is driven into the ground as an outer casing that receives the driving force from the Geoprobe hammer. The second, smaller set of rods are placed inside the outer casing to hold a sample liner in place as the outer casing is driven into the sub-surface. This provides a sealed hole from which soil samples can be recovered without cross contamination even in collapsing holes or in the presence of groundwater.
