A Study of Correlation between SPT N-value and Exerted Electrical Energy Required for Ground Drilling II : Application Study (Field Pilot Test)

지반굴착에 소요되는 전기에너지와 표준관입시험 N값과의 상관관계 연구 II : 적용성 평가(현장시험시공)

  • Choi, Changho (Dept. of Geotechnical Engineering, Korea Institute of Construction Technology)
  • Received : 2012.12.04
  • Accepted : 2012.12.24
  • Published : 2012.12.30


In this application study, field pilot tests were performed to evaluate the validity of a proposed formula between the exerted electrical energy and SPT N-value based on the result of the basic study. Measurement sensors and recording system were developed to obtain exerted motor current and drilling depth in a field. By using the correlation formula proposed in the basic study, the measured motor current and boring speed were applied to predict SPT N-value and the predicted N-values were compared to SPT N-value of site exploration. From the comparisons it is verified that the exerted electrical energy to bore ground might be used to predict SPT N-value and pile tip location.


  1. Cho, C. W. (2010), Piling Engineering Practice, Engineer Book, pp.46-60.
  2. Choi, C., Cho, J., Chung, H., Lee, Y. (2007a), "SPT N-value Estimation from Exerted Electrical Motor Energy for Preboring Pile Installation," Proceedings of 7th Japnanese-Korean-French Seminar on Geo-Environmental Engineering, Grenoble, France, pp.293-298.
  3. Choi, C. (2012), "A Study of Correlation between SPT N-value and Exerted Electrical Energy Required for Ground Drilling : Basic Study (Laboratory Soil Box Test)", Journal of Korean Geosynthetics Society, under review process.
  4. Geotechnical Engineering Research Group (2003), Plan, design, and construction of pile foundation in practice, Gunsul-JeongBo, pp.456-463.
  5. Korea Nation Housing Cooperation (2004), Solutions of Structural Problems for Engineers, pp.40-48. (in Korean)
  6. Korea Patent (2006), Apparatus for measuring excavation depth for ground excavation equipment, Patent No.556673.
  7. Park, Y.-H., Kim, N.-Y. and Yook, J.-H. (2004), Design and Construction of SIP Method(II), Korea Expressway Corporation Research Report, pp.35-39.
  8. Architectural Institute of Korea (2004), Recommendations for Design of Building Foudnations-Japan Architecture, Originally published in Japan in 2001 by Architectural Institute of Japan, pp.389-391.
  9. Bowles, J. E. (1996), Foundation Analysis and Design, 5th Ed., McGraw-Hill, pp.154-162.