Thin-Walled Tube sampling in accordance with AASHTO T207 or ASTM D1587 is critical to retrieving undisturbed, in-situ samples used for laboratory testing for obtaining useful soil parameters for use in AASHTO design methodologies. Use undisturbed in-situ samples retrieved in accordance with AASHTO T 207 or ASTM D1587 for lab testing. Where fine-grained, or cohesive soils are observed collect ThinWalled Tube samples at intermediate locations between the SPT. Use 3 inch diameter Thin-Walled Tubes unless deviations are requested in investigation and approved by the Bridge Division Geotechnical Branch. Indicate on logs length of sample collected (recovery) and if tube was unable to push the full 24” of undisturbed sample as specified by procedure.

Typically, samples can be extruded in the field and wrapped to prevent moisture loss or sealed in plastic bags immediately after measuring recovery length and obtaining pocket penetrometer and/or torvane measurements. Project specific guidelines may dictate that tube samples be capped or waxed at the ends and cut open in the lab.