Shear Strength Parameters in Clay Soils from Cone Penetration and Lab Tests

摘要

The interpreted undrained shear strength obtained from in-situ static cone penetration test (CPT) data was found to be in good agreement with laboratory tests conducted on samples from adjacent boreholes at two case study sites in northern Minnesota. A series of CPT soundings were taken at the two sites, each with companion boreholes to compare interpreted shear strength values against traditional standard penetration test (SPT) borings and lab tests. Unconfined compression, direct shear, and direct simple shear tests were conducted on normally consolidated clay soils. The undrained shear strength derived from CPT data was generally in closest agreement with the direct simple shear test results. The use of CPT investigation techniques at the two sites minimized the amount of traditional drilling and sampling required and provided a more detailed site investigation than would have been possible with conventional techniques alone. The use of CPT methods also resulted in a total cost savings, estimated at $50,000, associated with reduced time in the field at the two case study sites.