Pocket Penetrometer
Overview
Compressional strength in sediments the maximum vertical pressure (uniaxial load) a sediment sample can withstand before failing, fracturing, or undergoing permanent deformation and can be measured by a penetrometer. Compressional strength is a measure of the internal resistance to being squeezed, which directly impacts geological structural integrity. The penetrometer is suitable for sediment not affected by cementation (e.g., saturated, clay-rich, soft sediment).
Instrument Make and Model
Soiltest Inc. EI29-3729
Estimated Measurement Time
- Sample Measurement: ~1 min/measurement
Principles & Analytical Capabilities
Compressional strength is generally measured on section halves using the Pocket Penetrometer handheld instrument. Shear strength can be calculated from the measured compressional strength. Compressional strength measurements should be considered only approximate, particularly because the influence of pore pressure changes during the undrained experiment cannot be estimated.
Data Generated
Data components:
- Compressional strength: strength value at the failure point of the sample, determined by maximum torque (N.m) divided by the adapter foot constant (m3).
- Penetration direction: orientation of penetration (orthogonal to the shear experiment plane). Values include "X", "Y", "Z", or "-Z".
- Adapter foot identifier: whether an adapter was used on the penetrometer for the measurement: "yes" or "no".
Data files:
- Results (CSV): manually recorded data by user.
Data Example
Procedures & Manuals
References
1 Coggon, R. M., Teagle, D. A. H., Sylvan, J. B., Reece, J., Estes, E. R., Williams, T. J., Aizawa, M., Albers, E., Amadori, C., Belgrano, T. M., Borrelli, C., Bridges, J. D., Carter, E. J., Christeson, G. L., D'Angelo, T., Dinarès-Turell, J., Doi, N., Estep, J. D., Evans, A., … Zhang, G. (2024). IODP Expedition 393 Compressional strength (penetrometer) [Data set]. International Ocean Discovery Program. https://doi.org/10.5281/zenodo.10680620