A Study of Correlation between SPT N-value and Exerted Electrical Energy Required for Ground Drilling I : Basic Study (Laboratory Soil Box Test)

지반굴착에 소요되는 전기에너지와 표준관입시험 N값과의 상관관계 연구 I : 기초연구(실내토조실험)

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


Ground drilling is a common method to conduct site investigation, soil improvement, and pile installation. In the point of construction ground drilling requires electrical energy to drill a hole in ground in which the energy exerts into the motor located on the head of auger and generates rotational power. In this paper it is verified that the exerted electrical energy is closely related to the strength characteristics of ground. Measurement sensors, recording system, and drilling system were developed to obtain exerted motor current and drilling depth and laboratory soil box tests were carried out. The measured motor current and boring depth were applied to predict SPT N-value and the prediction results were compared to SPT N-value of laboratory tests. The test results show that the exerted electrical energy to bore ground be a good index to estimate SPT N-value.


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