• Title/Summary/Keyword: Combined resonant and torsional shear test

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Analysis of Static and Dynamic Characteristics of Reinforced Roadbed Materials (철도 강화노반재료의 정ㆍ동적 특성 분석)

  • 황선근;신민호;이성혁;이시한;최찬용
    • Journal of the Korean Society for Railway
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    • v.3 no.1
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    • pp.34-41
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    • 2000
  • The analysis of static and dynamic characteristics of reinforced roadbed materials was performed through model and laboratory tests. The strength characteristic of reinforced roadbed materials such as HMS-25 and soil were investigated through the unconfined axial compression test, the model soil box test and the combined resonant column and torsional shear test. The unconfined axial compression strength of HMS-25 shows a steady increasement in strength due to the chemical hardening reaction between HMS-25 and water. The result of model soil box test reveals that railroad roadbed of HMS-25 is better than that of soil in several aspects, such as, bearing capacity and settlement. The combined resonant column and torsional shear test result indicates that shear modulus of HMS-25 and soil increase with the power of 0.5 to the confining pressure and linear relationship to normalized shear modulus and damping ratio.

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Evaluation of Applicability of HMS-25 as the Railroad Roadbed Material (철도 노반재로서의 수경성 입도 조정 고로슬래그(HMS-25)의 적용성 평가)

  • 황선근;이성혁;이시한;최찬용
    • Journal of the Korean Geotechnical Society
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    • v.16 no.1
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    • pp.157-165
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    • 2000
  • The applicability and performance of HMS-25 as the railroad roadbed materials were evaluated through the model and laboratory tests. The uniaxial compression test of HMS-25, model soil box test, and combined resonant column and torsional shear test were performed for static and dynamic analysis of railroad roadbed. The uniaxial compression test result of HMS-25 shows steady increase in strength due to hardening chemical reaction between HMS-25 and water. The result of model soil box test reveals that railroad roadbed of HMS-25 is better than that of soil in several aspects such as bearing capacity and settlement. The combined resonant column and torsional that shear test result indicates that shear modulus of HMS-25 increases with the power of 0.5 to the confining pressure and that shear modulus increases with the increase of curing period.

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Identifying Strain Associated with Damping Ratio from Tosional Test Using a Combined Damping Model (복합감쇠모델을 이용한 비틂 시험기로 얻은 감쇠비에 상응하는 변형률 산정)

  • Bae, Yoon-Shin
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.1
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    • pp.43-55
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    • 2008
  • The complexity of determining strain associated with shear modulus and damping ratio in torsional tests has been resolved by means of several approaches. Particularly, the modified equivalent radius approach is adequate to when generating the plots of equivalent radius ratio versus strain more effectively over any range of strains in resonant column and torsional shear (RC/TS) tests. The modified equivalent radius approach was applied for hyperbolic, modified hyperbolic, and Ramberg-Osgood models in evaluating damping ratio. Results showed that using a single value of equivalent radius ratio based on conventional equivalent radius approach is not appropriate. A new model was developed to consider the soil damping behavior at small strains as well as hysteretic damping and it was attempted to determine adjustments are required in evaluating strain associated damping when combining the two damping components.

Evaluation of Nonlinear Deformational Characteristics of Soils from Laboratory and Field Tests (실내시험 및 현장시험을 통한 지반의 비선형 변형특성 평가)

  • 김동수;권기철
    • Geotechnical Engineering
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    • v.13 no.5
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    • pp.89-100
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    • 1997
  • It is very improtant to evaluate the reliable nonlinear deformational characteristics of soils not only in the analysis of geotechnical structures under working stress conditions but also for the soil dynamic problems. Field testings such as crosshole and pressuremeter tests can be used to determine the modulus of soils under in-situ conditions, but it is not possible to determine the modulus over the entire strain amplitude range. Laboratory methods such as resonant column 1 torsional shear test can be used to determine the modulus over the whole strain amplitude range, but it is very difficult to obtain the representative undisturbed samples on the sixte. For the reliable evaluation of nonlinear deformation characteristics of soils on a typical site, small strain modulus obtained from field testy and nomalized modulus reduction curve determined by laboratory bests need to be combined. In this paper, laboratory and Held testy were performed at a sixte which consisted of granite wearthered residual boils to evaluate the nonlinear deformational characteristics of coils such as the effects of strain amplitude, loading frequency, confining pressure and sample disturbance. It has been shorn that when the effects of these factors are properly taken into account, the stiffness values evaluated by various field and labrotary tests are comparable to each other fairly well. Finally, the procedure to evaluate the nonlinear deformstional characteristics of the sixte was proposed.

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