Vision Cone Penetrometer for Direct Subsurface Soil Observation

• Published in: Journal of geotechnical and geoenvironmental engineering Vol. 123; no. 11; pp. 1074 - 1076
• Main Authors: Raschke, Scott A, Hryciw, Roman D
• Format: Journal Article
• Language: English
• Published: New York, NY American Society of Civil Engineers 01.11.1997
• Subjects: Applied sciences; Buildings. Public works; Exact sciences and technology; Geotechnics; Soil investigations. Testing; TECHNICAL NOTES; Penetrometer; Soil testing; Standard test; System description; Property of soil; Engineering geology; Mechanical properties; Video technique; Penetration test; Method study
• ISSN: 1090-0241; 1943-5606
• DOI: 10.1061/(ASCE)1090-0241(1997)123:11(1074)

The cone penetration test (CPT) has gained wide acceptance for geotechnical site characterization and measurement of mechanical soil properties in situ. However, unlike the standard penetration test (SPT), soil specimens are not obtained in the CPT. Therefore, the soil type can only be estimated through empirical correlations with CPT sounding data or by retrieving field specimens adjacent to the test location. This technical note describes a new vision cone penetrometer (VisCPT), which permits observation and recording of subsurface images in real time as the VisCPT is pushed into the ground at the CPT standard advance rate of 20 mm s. A high- and low-magnification miniature charge-coupled device (CCD) camera system housed within the VisCPT provide images with fields of view of 2.3 and 18 mm, respectively (measured diagonally). A field video recording system allows the video sequence from each camera to be recorded in real time on two super VHS (S-VHS) format video recorders. Examples of images acquired in situ are presented.