Effect of surface texturing on CPT friction sleeve measurements

As the use of the cone penetration test (CPT) has increased for geotechnica l site characterization, significant research has been performed to identif y and control the factors that affect the tip (q(c)), sleeve (f(s)), and po re pressure (u) measurements. However, a number of factors that affect the friction sleeve have yet to be understood, appreciated, and accounted for i n penetrometer designs. This paper highlights a number of these issues, wit h specific attention centered on the effect of surface texturing on the fri ction sleeve measurement. An understanding of the role of surface roughness on soil-geomaterial interfaces provides a framework for analyzing the effe ct on the friction sleeve measurement and could provide a basis to improve its design. A series of CPT soundings were performed in the southeast Unite d States with conventional smooth and textured friction sleeves. Results in dicate that friction measurements with a textured sleeve are 70% greater on average than the value obtained with a conventional smooth friction sleeve in sand and provide a basis for developing new design procedures where int erface values are required.