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2024 Vol.40, Issue 6 Preview Page
Validation of In-situ Modulus Detector for Subsurface Characterization

지반 특성을 파악하기 위한 원위치 강성분석기의 검증

Hong Ju Kim1
,
Dong-Ju Kim2
,
Yong-Hoon Byun3*
김 홍주1
,
김 동주2
,
변 용훈3*
1Undergraduate Student, Dept. of Agricultural Civil Engineering, Kyungpook National Univ.
2Member, Ph.D. Candidate, School of Civil, Environmental and Architectural Engineering, Korea Univ.
3Member, Associate Prof., Dept. of Agricultural Civil Engineering, Kyungpook National Univ.
1비회원, 경북대학교 농업토목공학과 학사과정
2정회원, 고려대학교 건축사회환경공학과 박사수료
3정회원, 경북대학교 농업토목공학과 부교수
*Corresponding Author
31 December 2024. pp. 151-159
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Abstract

The mechanical properties of subgrade soils are crucial for determining road structural stability and bearing capacity. The resilient modulus and permanent deformation are key indicators of pavement performance. In this study, an in situ modulus detector is used to analyze the changes in the mechanical properties according to various depths of the subgrade soils, comparing the resilient modulus and permanent displacement with dynamic cone penetration indices. The in situ modulus detector consists of a cone tip, driving rod, and hammer guide, enabling effective transmission of the kinetic energy through a rubber buffer. The detector also uses four strain gauges and an accelerometer at the cone tip to measure the dynamic loads and displacements. Model subgrades with three different dry unit weights are prepared, and penetration tests are performed using an in situ modulus detector and a standard dynamic cone penetrometer. The results show that as the dry unit weight and penetration depth increase, the resilient modulus increases, whereas the permanent deformation decreases. Furthermore, a negative correlation is observed between the resilient modulus and the permanent deformation. These findings suggest that an in situ modulus detector can effectively evaluate the resilient modulus and permanent deformation of subgrade soils in the field.

Keywords
Dynamic responses
In situ tests
Permanent deformation
Resilient modulus
Subgrade soils

노상토의 역학적 특성은 도로의 구조적 안정성과 지지력을 결정하는 핵심 요소이며, 회복탄성계수와 영구변형은 중요한 포장 성능 지표로 여겨진다. 따라서, 본 연구에서는 원위치 강성분석기를 활용하여 노상토의 깊이별 변화를 특성화하고, 산정된 회복탄성계수 및 영구변위를 동적콘관입지수와 비교분석하였다. 원위치 강성분석기는 원추형 선단부와 관입 롯드, 그리고 해머의 낙하가이드로 구성되어 있으며, 고무 버퍼를 통해 운동에너지를 효율적으로 전달한다. 또한, 원위치 강성분석기에서는 선단부의 변형률계와 가속도계를 이용하여 동적 하중과 변위를 측정할 수 있다. 다양한 건조단위중량의 사질토 모형지반을 조성한 후, 원위치 강성분석기와 표준 동적콘관입기를 이용하여 관입실험을 수행하였다. 실험 결과, 건조단위중량과 관입 깊이가 증가할수록 회복탄성계수는 증가하는 반면 영구변위는 감소하는 경향을 보였다. 또한, 회복탄성계수와 영구변위 간에는 음의 상관관계가 확인되었다. 이를 통해, 원위치 강성분석기는 현장에서 노상토의 역학적 특성을 평가하는데 유용하게 활용될 수 있을 것으로 기대된다.

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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 40
  • No :6
  • Pages :151-159
  • Received Date : 2024-12-13
  • Accepted Date : 2024-12-16
  • DOI :https://doi.org/10.7843/kgs.2024.40.6.151
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