Senior research civil engineer, Center for Building Technology, National Bureau of Standards, Gaithersburg, MD
Graduate research assistant, Cornell University, Geotechnical Research Lab, Hollister Hall, Ithaca, NY
Helical test probes of different sizes suitable for shallow (1.8-m) in-situ soil exploration and compaction control were developed and tested in different soils alongside traditional in-situ tests, including Standard Penetration tests (SPT), cone penetration tests (CPT), dilatometer tests (DMT), and in-situ density tests. The helical probe test (HPT) is a quick and economical test, which can be performed by a single person in less than 10 min, making it very attractive for construction field testing on geotechnical projects. The torque necessary to insert the probe is used as a measure of soil characteristics. Preliminary studies indicate that the HPT test correlates well with the SPT test and the correlation is not sensitive to the soil type (particle size); the HPT test correlates well with the CPT test, but the correlation is sensitive to the soil type; and the HPT/SPT and HPT/CPT correlations are consistent with existing data on SPT/CPT correlations. After site calibration, the HPT torque can be used to estimate relative compaction and in-situ density of compacted soils.
Paper ID: GTJ10004J