Apex Designs

1375 Boomer Circle
Suwanee GA 30024, USA
Tel: 678 910 2354, Fax: 770 622 0917
Email: info@apexdesigns.net
Web: http://www.apexdesigns.net/fabrication.html

Service: Supplier of Geotechnical in-situ testing equipments

About Apex Designs

Located just north of Atlanta GA, Apex Designs has been providing engineering, design, and fabrication services to the scientific, medical, and manufacturing industries since 2005.  The diversity of our engineering background combined with hands-on manufacturing skills allows us to create innovative and effective solutions that balance functionality with aesthetics and cost

Helical Probe Test

Abstract
Soil exploration and compaction testing by the helical probe test (HPT) has become popular with Geotechnical Engineers for providing a quick and accurate method of determining soil properties at relatively shallow depths. The HPT test is attractive for geotechnical in-situ testing because it is very portable and can be efficiently performed by just one person. The HPT method is particularly useful for conducting studies in areas with limited vehicle access and is very popular for pre-construction footing inspections.   Preliminary ASTM tests have determined favorable correlations to the Standard Penetration Test (SPT) and Cone Penetration Test (CPT) using empirical calibration.  HPTs have been used successfully in both offshore and onshore applications.

Function
The HPT is used to measure the compaction properties of a soil by measuring its relative shear properties.  First,  the probe is inserted to the desired depth.  The design of the HPT allows for the unit to be driven to the desired test depth very quickly by a cordless drill.  (Alternatively, the unit can be inserted into a previously bored hole).  Once the probe is inserted to the desired depth, a beam style torque wrench is fitted to the hex coupler.  The HPT is then rotated by the torque wrench while the average amount of torque required to turn the probe is noted.  The value of torque is used as a measure of the soil's compaction characteristics.   Setup calibration of the HPT is achieved by correlating side by side data from the user's preferred standardized test method.  Calibrations are frequently performed using the SPT and the CPT test.  

HPT Construction
Apex Designs is the leader in HPT manufacturing and has been supplying Geotechnical and Civil Engineers quality HPT products for over a decade.  Apex Designs' HPTs are CAD designed,  machined in-house to our exacting specifications,  and TIG welded in fixtures to assure consistency. Our 19mm diameter "TP-3" units are designed to accommodate the most useful range of soil applications.  

» Apex Designs - Compaction Test (pdf)