Field and laboratory measurements of seismic and mechanical properties of frozen ground

Geotechnical and geophysical investigations of the frozen seabottom sediments were carried out during the spring of 1983 and 1984 by the Geological Survey of Canada in the southern part of the Beaufort Sea, northwestern Canada. Uphole seismic and seabottom refraction surveys were made in the boreholes and their vicinities, yielding borehole compressional velocities between 1445 and 2060 m/s. Acoustic wave velocity tests, conducted on core samples from the boreholes, were made in the field and in the laboratory resulting in compressional wave velocities between 1370 and 2050 m/s, in good agreement with the uphole seismic measurements. Field shear vane tests and unconfined compression tests, as well as standard engineering property tests, were carried out on undisturbed and partly disturbed core samples. The results showed that shear strength values, ranging less than 10 to 90 kPa, are highest farther offshore and at zones of highly consolidated sediments. Geophysical techniques were unable to identify these thin (less than 1 m) but laterally extensive zones.