Rod effects on transferred energy into SPT sampler using smart measurement system

Geunwoo Park , Namsun Kim , Won-Taek Hong , Jong-Sub Lee

Abstract

To improve the accuracy of the standard penetration test (SPT) results, smart measurement system, which considers the energy transfer ratio into the sampler (ETRSampler), is required. The objective of this study is to evaluate the effects of joints and rod length on the transferred energy into the sampler. The energy transfer ratios into the rod head (ETRHead) and ETRSampler, and the energy ratio from the head to the sampler (ERHS) were obtained using energy modules, which were installed at the rod head and above the SPT sampler. Linear regression analyses are conducted to correlate the ERHS with the number of joints, rod length, and SPT N-values. In addition, the dynamic resistances are calculated using both transferred energies into the rod head and into the sampler, and are compared with the corrected cone tip resistance measured from the cone penetration test (CPT). While the ETRHead are generally constant, but the ETRSampler and ERHS gradually decrease along the depth or the number of joints, except at certain depths with high SPT N-values. Thus, the ERHS can be estimated using the number of joints, rod length, and SPT N-values. The dynamic resistance evaluated by ESampler produces a better correlation with the corrected cone tip resistance than that by EHead. This study suggests that transferred energy into the SPT sampler may be effectively used for more accurate subsurface characterization.

Key Words

dynamic resistance; energy correction; energy module; standard penetration test (SPT); transferred energy

Address

(1) Geunwoo Park, Namsun Kim, Jong-Sub Lee — School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
(2) Won-Taek Hong — Department of Civil and Environmental Engineering, Gachon University, 1342, Seongnam-daero, Sujeong-gu , Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.

PDF Viewer

Preview is limited to the first 3 pages. Sign in to access the full PDF.

← Back to Volume 30, No. 2