Piezocone Technology: Downhole Geophysics For The Geoenvironmental Characterization Of Soil

The electronic cone penetration test with pore pressure measurement, commonly referred to as the piezocone test or<br>CPTU, has been established by the worldwide geotechnical community as the premier stratigraphic logging tool for<br>most soil conditions. Besides stratigraphic information, the piezocone also provides accurate estimates of key<br>geotechnical parameters and yields extensive information on the physical groundwater regime. Groundwater<br>parameters assessed include accurate location of the phreatic surface, determination of in-situ gradients, and estimates<br>of hydraulic conductivities.<br>In recent years, additional geophysical measurement capabilities have been added to the standard piezocone. These<br>additions have included seismic pick-ups (geophone or accelerometer) for downhole and/or cross-hole seismic wave<br>measurements and resistivity modules which can be modified to include induced-polarization measurements. With<br>these additions, current piezocone technology represents an unparalleled means of accurately, rapidly ti<br>economically geoenvironmentally characterizing most natural and man-made soil deposits.<br>This paper introduces traditional piezocone technology and summarizes recent key advances with this geophysical<br>logging tool. A brief case study is presented to demonstrate the technological and economical advantages of the<br>piezocone over more traditional site characterization methods.