Rotation speed analysis in SPT-T test by type of soil

Abstract

One of the main purposes of the Standard Penetration Test (SPT) is related to prediction of load capacity of foundations. In addition, the SPT-T was proposed using a torquemeter device in order to break the adhesion of soil sampler after the end of each SPT. This measurement can be used to calculate the amount of lateral friction improving foundations design. The rotation speed is analyzed to set its variation range and its influence on the torque measurement is assessed based on soil type. First, a theoretical study was conducted. Secondly, analysis were performed with data obtained from a system that simultaneously enabled the acquisition of torque measurement and its corresponding rotation speed resulting in 426 curves in seven sites with different geotechnical characteristics. The analysis of rotation degrees had considered the geotechnical profile of each site and then they were faced with N; maximum torque (Tmax); residual torque (Tres); Tmax/N ratio; and finally type of soil. A statistical analysis was done and then in conclusion this study will improve the SPT-T implementation procedure.