• Title/Summary/Keyword: Resonant Column Test

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Evaluation of Ground Improvement on Sands at Yongjong Island Geotechnical Experimental Site (영종도 지반공학 야외시험장에서의 사질토지반 개량효과 평가)

  • 김동수;박형춘;김영웅;김수일
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.439-446
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    • 1999
  • In situ experimental studies were Performed at Yongjong Island Geotechnical Experimental Site to evaluate the ground densification on sand deposited. Standard penetration test, cone penetration test, and SASW test were performed and soil profiles and quality of ground improvements were evaluated. The feasibility of applying SASW method were verified by comparing test results. The evaluation technique of in-situ density using SASW and resonant column tests was proposed, and the reliability of proposed method was verified by performing case studies.

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Dynamic Deformation Characteristics of Fiber Reinforced Soils Using Resonant Column Tests (공진주 시험을 이용한 섬유보강토의 동적변형특성)

  • Chang, Pyoung-Wuck;Heo, Joon;Park, Young-Kon;Cha, Kyung-Seob;Woo, Chull-Woong
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.349-352
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    • 2002
  • In this paper, dynamic properties of fiber reinforced soils were investigated at shearing strains between $10^{-4}%\;and\;10^{-1}%$ using resonant column test. Resonant column test has been widely used as a primary laboratory testing technique in investigating dynamic soil properties expressed in term of shear modulus and material damping. At strains above elastic threshold, the variations of shear modulus(G) and damping ratio(D) were investigated. Based on test results, the small strain shear modulus($G_{max}$) and damping ratio($D_{min}$) were determined and the effects of confinement on $G_{max}$ and $D_{min}$ were characterized.

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Adoption of the large scale free-free resonant column test (대형 공진주 시험 장비의 적용)

  • Park, In-Beom;Park, Chul-Soo;Mok, Young-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.626-633
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    • 2009
  • A large scale resonant column testing equipment is under development. The would-be equipment is aiming to test 150mm-diameter specimens, which can contain as large a grain size as 25mm. Such a large specimen is hardly excitated with the existing fixed-free end condition because the torsional force cannot be effectively coupled to the specimen. The specimen will be rather resonated with free-free condition and the scheme is implemented with a rotational bearing installed between coil-magnet exciter and base pedestal. Presently the equipment was assembled and is under calibration with a cylindrical brass specimen.

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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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A Solution to Large Strain Resonant Column and Torsional Shear Tests Apparatus (대변형율 시험을 위한 공진주/비틂전단 시험기의 해결방안)

  • Bae, Yoon-Shin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.3C
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    • pp.103-108
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    • 2011
  • In this study, the limitations of large strain resonant column and torsional shear tests apparatus are described and solutions to the limitations are also described. The limitations are rotational distance, limited torque, and measurable deformation system, respectively. To resolve the rotational distance, the bottom platen was modified. And the four-armed drive plate was modified into eight-armed drive plate and the drive coil connection was changed to obtain powerful torque.

A Study on the Bottom Ash Characteristics of Resonant Column Tests (공진주시험을 통한 Bottom Ash의 특성 연구)

  • Yoon, Won-Sub;Chae, Young-Su
    • Journal of the Korean Geotechnical Society
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    • v.27 no.6
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    • pp.81-95
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    • 2011
  • This study investigates relative density test of standard sand and bottom ash which were devided into No.40, No.60, No.100, No.200 and resonant column tests were conducted for samples with the relative density of 40%, 55%, and 70% on the basis of the test results. Resonant column tests were also conducted for each residual bottom ash which contains the passing sample of No.200 with the relative density of 55%. By compressing each residual sample with the compaction energy of A-compact mold test, the passing percentage of No.200 sieve increased up to 30%, which led to the adjustment of relative density to 10%, 20%, and 30%. Test results show that maximum shear modulus and damping ratio of bottom ash are smaller than those of standard sand because crushing strength and unit weight of the former are smaller than those of the latter.

Verification of the large scale, free-free resonant testing equipment using Jumunjin sand (주문진 표준사를 이용한 대형 공진주 시험 장비의 검증)

  • Park, In-Beom;Park, Chul-Soo;Mok, Young-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.1415-1424
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    • 2009
  • Measuring dynamic properties of gravel-sized materials demands large specimens. Due to the difficulties in experiment as well as equipment, the dynamic properties of gravel-sized material has rarely been investigated. To realize free-free end condition more properly and stabilize specimen during testing with new specimen support system, a free-free resonant column testing device, which is capable of testing gravel-sized materials and constraining a specimen in free-free boundaries, is developed. We report the calibration of the equipment and preliminary testing results on Jumunjin sand. The testing data are compared with the previous data obtained from the existing fixed-free resonant column test.

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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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Evaluation Technique of Ground Densification on Sand Deposit using SASW and Resonant Column Tests (표면파시험과 공진주시험을 이용한 사질토지반 개량평가 시스템의 개발)

  • 김동수;박형춘;김성인
    • Journal of the Korean Geotechnical Society
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    • v.15 no.1
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    • pp.41-52
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    • 1999
  • In order to assess the quality and depth of ground densification by compaction, SPT and/or CPT are performed before and after compaction. Both methods are intrusive and one point tests, require a substantial time to evaluate a large area, and their results are quite dependent on the operation technique and soil type. In this paper, the quality and extent of ground densification by compaction was evaluated by using in situ SASW test and laboratory resonant column (RC) test results. SASW test was used to determine the shear wave velocity profiles before and after compaction, and RC test was adopted to determine the correlation between the normalized shear wave velocity and the density of the site, which is almost uniquely independent of confinement. Testing and data reduction procedures of both tests were discussed, and a simplified evaluation procedure of ground densification was proposed. Finally, the feasibility of the proposed method was verified by performing field study at Inchon International Airport Project. Field densities determined by the proposed method matched well with those determined by sand cone tests.

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