Seismic cone penetration testing in the near offshore of the MacKenzie Delta

Abstract

A study was performed in the shallow waters of the MacKenzie Delta area near Tuktoyaktuk, N.W.T., Canada, to evaluate equipment, test procedures, and techniques using a seismic cone penetrometer and operating on the landfast ice in winter. Seismic cone penetration testing was performed to determine the compressional and shear wave velocities of the subsurface sediments using a downhole technique. Several seismic sources and receivers were tested to evaluate their effectiveness. Typical results are presented and briefly discussed. Key words: downhole, seismic, P-wave, S-wave, velocity, in situ, measurement, shallow offshore, cone penetration test.

Seismic cone penetration test

“…As for the P-waves, they are out of range, varying between 0 to 450 m/s for sand and between 0 to 220 m/s for clay. As highlighted by (R. G. Campanella, 1986), the combination of the seismic downhole method with the CPTu provide rapid and reliable means XVI of determining stratigraphic, soil properties and velocity information in one SCPTu. The addition of seismic measurements significantly can improve the ability of the CPTu, meaning the bearing capacity is obtained from the CPTu and the soil deformation (elastic parameters) are obtained from the SCPTu.…”

“…The first blow (for example, the left side) represents the seismic record from the SPCTu as seen in Figure 25 part A. To confirm that a real shear wave was obtained, another record is taken by hitting on the other side (in this case, the right) and if the data is correct it should look as Figure 25 It has been found that the polarity of the source greatly facilitates the identification of the S-wave and the time for the first crossover point (shear wave changes sign) is easily identified from the polarized waves (forward and reverse) and provides the most repeatable reference arrival time, (R. G. Campanella, 1986). Figure 26: Seismic analysis using reverse polarity, (Geotech, 2004) The shear wave velocity is readily computed by dividing the distance between two pairs of receivers by the time for the signal to travel from the one receiver to the next.…”

Model Uncertainties of SPT, CPT, and VS-based Simplified Methods for Soil Liquefaction Assessment

“…Compared with the SPT-N methods, the CPT-q c methods emerged later but piezocone penetration tests (CPTU) have many advantages (National Science Foundation 1994) and have attracted considerable attention in geotechnical engineering (e.g., Campanella et al 1987;Kulhawy and Mayne 1990;Chen and Mayne 1996;Mayne 2006;Robertson 2009Robertson , 2016 such that CPT-q c methods have gradually evolved in a diverse manner and matured with an increasing amount of investigative data of lique ed and nonlique ed sites. Olsen (1997) utilized the liquefaction data from case histories (Shibata et al 1988;Stark and Olson 1995;Suzuki et al 1995) to develop a technique for evaluating liquefaction resistance from CPT soundings along with a soil classi cation system, which pioneered CPT-q c research methods.…”

Model Uncertainties of SPT, CPT, and VS-based Simplified Methods for Soil Liquefaction Assessment

“…Compared with the SPT-N methods, the CPT-q c methods emerged later but piezocone penetration tests (CPTU) have many advantages (National Science Foundation 1994) and have attracted considerable attention in geotechnical engineering (e.g., Campanella et al 1987; Kulhawy and Mayne 1990; Chen and Mayne 1996;Mayne 2006;Robertson 2009Robertson , 2016) such that CPT-q c methods have gradually evolved in a diverse manner and matured with an increasing amount of investigative data of lique ed and nonlique ed sites. Olsen (1997) utilized the liquefaction data from case histories (Shibata et al 1988;Stark and Olson 1995;Suzuki et al 1995) to develop a technique for evaluating liquefaction resistance from CPT soundings along with a soil classi cation system, which pioneered CPT-q c research methods.…”