원위치 동적강성 분석기의 개발 및 성능평가
Development and Performance Evaluation of In-situ Dynamic Stiffness Analyzer
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초록
Stiffness characteristic of subgrade is one of the most important aspects for the design and evaluation of pavement and railway. However, adequatefield testing methods for evaluating the stiffness characteristics of the subgrade have not been developed yet. In this study, an in-situ dynamic stiffnessanalyzer (IDSA) is developed to evaluate the characteristics of subgrade stiffness along the depth, and its performance is evaluated in elastic materialsand a compacted soil. The IDSA consists of a falling hammer system, a connecting rod, and a tip module. Four strain gauges and an accelerometerare installed at the tip of the rod to analyze the dynamic response of the tip generated by the drop of hammer. Based on the Boussinesq’s method,the stiffness and Young’s modulus of the specimens can be calculated. The performance of IDSA was tested on three elastic materials with differenthardness and a compacted soil. For the repeatability of test performance, the dynamic signals for force and displacement of the tip are averaged fromthe hammer impact tests performed five times at the same drop height. The experimental results show that the peak force, peak displacement, and theduration depend on the hardness of the elastic materials. After calculating the stiffness and elastic modulus, it is revealed that as the drop height ofhammer increases, the stiffness and elastic moduli of MC nylon and the compacted soil rapidly increase, while those of urethanes less increase.
Abstract
Stiffness characteristic of subgrade is one of the most important aspects for the design and evaluation of pavement and railway. However, adequatefield testing methods for evaluating the stiffness characteristics of the subgrade have not been developed yet. In this study, an in-situ dynamic stiffnessanalyzer (IDSA) is developed to evaluate the characteristics of subgrade stiffness along the depth, and its performance is evaluated in elastic materialsand a compacted soil. The IDSA consists of a falling hammer system, a connecting rod, and a tip module. Four strain gauges and an accelerometerare installed at the tip of the rod to analyze the dynamic response of the tip generated by the drop of hammer. Based on the Boussinesq’s method,the stiffness and Young’s modulus of the specimens can be calculated. The performance of IDSA was tested on three elastic materials with differenthardness and a compacted soil. For the repeatability of test performance, the dynamic signals for force and displacement of the tip are averaged fromthe hammer impact tests performed five times at the same drop height. The experimental results show that the peak force, peak displacement, and theduration depend on the hardness of the elastic materials. After calculating the stiffness and elastic modulus, it is revealed that as the drop height ofhammer increases, the stiffness and elastic moduli of MC nylon and the compacted soil rapidly increase, while those of urethanes less increase.
참고문헌 (19)
- American Society for Testing and Materials, "Standard test methods for laboratory compaction characteristics of soil using modified effort, D1557", ~ (2012)
- Yong-Hoon Byun, "Instrumented Dynamic Cone Penetrometer Corrected with Transferred Energy into a Cone Tip: A Laboratory Study", Geotechnical Testing Journal, 36(4), pp.20120115~ (2013), ASTM International[DOI]
- Byun, Y. H., "Active layer characterization by instrumented dynamic cone penetrometer in Ny-Alesund, Svalbard", Cold Regions Science and Technology, 104, pp.45~53 (2014)[DOI]
- 최찬용, "소형 FWD와 반복평판재하시험에서의 변형계수(Ev2)와의 상관관계 평가", 한국지반신소재학회 논문집, 10(3), pp.33~41 (2011), 한국지반신소재학회
- C.R.I. CLAYTON, "Stiffness at small strain: research and practice", Géotechnique, 61(1), pp.5~37 (2011), Thomas Telford Ltd.[DOI]
- Amr F. Elhakim, "The use of light weight deflectometer for in situ evaluation of sand degree of compaction", HBRC Journal, 10(3), pp.298~307 (2019), Informa UK Limited[DOI]
- Paul R. Fleming, "Review of Lightweight Deflectometer for Routine in Situ Assessment of Pavement Material Stiffness", Transportation Research Record: Journal of the Transportation Research Board, 2004(1), pp.80~87 (2007), SAGE Publications[DOI]
- Hoffmann, O., "Enhancements and verification tests for portable deflectometers", MN, 2003, pp.5~8
- 홍원택, "크로스홀 형태의 동적 콘 관입기를 이용한 노반의 강성특성 평가", 한국지반공학회논문집, 34(2), pp.55~63 (2018), 한국지반공학회[DOI]
- Hong, W. T., "Development of cone penetrometer for shear wave velocity assessment of track substructures", Journal of the Korean Society for Railway, 5, pp.781~791 (2015)[DOI]
- 강희복, "소형FWD를 이용한 노상토의 동적변형계수와 현상 CBR의 상관 연구", 한국구조물진단유지관리공학회 논문집, 12(2), pp.149~155 (2008), 한국구조물진단유지관리공학회
- 김대상, "지반반력계수(K30)와 변형률계수(Ev)에 대한 고찰", 한국철도학회논문집, 10(3), pp.264~270 (2007), 한국철도학회
- 김동수, "반복식 평판재하시험을 이용한 노상토의 현장 변형계수 평가", 한국지반공학회논문집, 21(6), pp.67~80 (2005), 한국지반공학회
- 김규선, "평판재하시험, 흙강성측정기 및 동적콘관입시험기를 이용한 노상토의 탄성계수 비교", 한국지반공학회논문집, 31(3), pp.63~72 (2015), 한국지반공학회
- 김연일, "경량 동적콘관입시험기를 이용한 화강풍화토의 다짐도에 따른 역학특성", 한국지반신소재학회 논문집, 13(3), pp.21~30 (2014), 한국지반신소재학회[DOI]
- Lee, K. S., "A study on the application of railway using Pagani cone test", Journal of the Korean Society for Railway, 2015, pp.462~468 (2015)[DOI]
- Nazzal, M., "Evaluating the potential use of a portable LFWD for characterizing pavement layers and subgrades", Geotechnical Engineering for Transportation Projects, 2004, pp.915~924 (2004)[DOI]
- Auckpath Sawangsuriya, "Laboratory Evaluation of the Soil Stiffness Gauge", Transportation Research Record: Journal of the Transportation Research Board, 1808(1), pp.30~37 (2002), SAGE Publications[DOI]
- Seyman, E., "Laboratory evaluation of in-situ tests as potential quality control", quality assurance tools, 2003