Evaluation of Undrained Shear Strength of Clay Using the CPTU Pore Pressure Method

Abstract

Difficulties in obtaining high-quality undisturbed soil samples have necessitated the increased use of cone penetration test (CPT) or piezocone penetration test (CPTU) to determine soil properties at geotechnical engineering sites. Undrained shear strength (a key parameter for most clay investigations) traditionally is evaluated by cone tip resistance or effective cone tip resistance. In this paper a method of using the clay's excess pore pressure was used to estimate the undrained shear strength. A correlation of pore pressure ratio and cone factor was discovered and compared with results from the published literature and with those from field vane tests.