• Title, Summary, Keyword: 동적콘관입시험

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Bearing Capacity of Pavement Foundation by Waste Lime Material using the Dynamic Cone Pentrometer (동적 콘관입시험기를 이용한 폐석회 혼합 도로노반 성토체의 현장 지지력 평가)

  • Kim, Young-Seok;Hong, Seung-Seo;Bae, Gyu-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.2
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    • pp.927-935
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    • 2011
  • In-situ California Bearing Ratio(CBR) test has been widely used for evaluating the subgrade condition in pavements. However, because the in-situ CBR test is expensive and takes time for operation, it is difficult to figure out the in-situ characteristics of subgrade strength in detail. For faster and economical operation, the Dynamic Cone Penetrometer(DCP) has been often utilized for estimating the subgrade strength in the field. The purpose of this paper is to determine the relationship between CBR value and DCP index of the embankment constructed with mixtures of soil and waste lime. Waste lime used in this study is producted as a by-product in the manufacturing process of making $Na_2CO_3$ from local chemical factory in Incheon. In this field measurement, the geotechnical tests such as field water content, field density, field CBR test, and dynamic cone penetration test were conducted.

A Study on Numerical Modeling of Dynamic CPT using Particle Flow Code (입자결합모델을 이용한 동적콘관입시험(DCPT)의 수치해석 모델링에 관한 연구)

  • You, Kwang Ho;Lee, Chang Su;Choi, Jun Seong
    • International Journal of Highway Engineering
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    • v.16 no.2
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    • pp.43-52
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    • 2014
  • PURPOSES : To solve problems in current compaction control DCPT(Dynamic Cone Penetrometer Test), highly correlated with various testing methods, simple, and economic is being applied. However, it、s hard to utilize DCPT results due to the few numerical analyses for DCPT have been performed and the lack of data accumulation. Therefore, this study tried to verify the validation of numerical modeling for DCPT by comparing and analyzing the results of numerical analyses with field tests. METHODS: The ground elastic modulus and PR(Penetration Rate) value were estimated by using PFC(Particle Flow Code) 3D program based on the discrete element method. Those values were compared and analyzed with the result of field tests. Also, back analysis was conducted to describe ground elastic modulus of field tests. RESULTS : Relative errors of PR value between the numerical analyses and field tests were calculated to be comparatively low. Also, the relationship between elastic modulus and PR value turned out to be similar. CONCLUSIONS : Numerical modeling of DCPT is considered to be suitable for describing field tests by carrying out numerical analysis using PFC 3D program.

The Evaluation of the Field Applicability of the Soil Improving Method Using the Environment-friendly Organic Acid Material (친환경 유기산 재료를 활용한 지반개량 공법의 현장 적용성 평가)

  • Lee, Jong-Hwi;Hong, Jong-Ouk;Jin, Youngguo;Chun, Byung-Sik
    • Journal of the Korean Geotechnical Society
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    • v.28 no.9
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    • pp.85-95
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    • 2012
  • The method of using organic acid is more environment-friendly for it improves the strength of the ground. The method of proliferating microbes makes soil particle bonded, finally improves the strength of the ground and decreasing permeability. Although there has been the research on the effect of strength increasing, there has never been a research on the evaluation of field application. In this paper, through the light drop weight test, the dynamic cone penetration test, the field density test, the variation of strength was investigated in the mixed ground with organic acid for 56 days. As the results of the field test, it was found that the strength and stiffness of the ground increased with organic acid, and that through SEM-EDS, the precipitation of calcium carbonate made by specified microbe obviously increased with organic acid material and so the ground was improved. Therefore, the sustainable development of this method needs to be analysed more in the future.

Application of Ground Penetrating Radar for Estimation of Loose Layer (지반 이완구간 추정을 위한 지하투과레이더의 적용)

  • Hong, Won-Taek;Kang, Seonghun;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.31 no.11
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    • pp.41-48
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    • 2015
  • An investigation of a void and a loose layer of the ground is essential in order to prevent the losses of life and properties caused by subsidence and sinkage of the ground. Recently, studies on the ground penetrating radar survey have been actively conducted in order to estimate the void and the loose layer of the ground. However, an error can be committed by contrarily predicting a dense ground and a loose layer because the ground penetrating radar estimates an interface depth between geo-materials that have different electrical impedances. In this study, a loose ground depth is estimated using the characteristics of the reflected electromagnetic wave obtained from the ground penetrating radar survey. To gather the signals according to the loose ground depths, the ground penetrating radar survey is conducted on a field which underwent a huge ground settlement. In addition, the dynamic cone penetration test is performed to verify the result of the loose ground depth estimation from the ground penetrating radar survey. From the analysis of the reflection characteristics of the electromagnetic wave, a phase of an electromagnetic wave reflected from a denser soil layer is found to be identical with that of the first measured signal. On the other hand, a phase of an electromagnetic wave reflected from the loose soil layer is found to be opposed to that of the first detected signal. The comparison between the dynamic cone penetration index and electromagnetic signals by the ground penetrating radar shows that the estimated depth of the loose or dense layer is perfectly matched with a high reliability. The ground penetrating radar survey and the signal analysis performed in this study can be used not only for the survey of interface depth between the discontinuity layers but also for the estimation of the loose layer.

Development and Application of Penetration Type Field Shear Wave Apparatus (관입형 현장 전단파 측정장치의 개발 및 적용)

  • Lee, Jong-Sub;Lee, Chang-Ho;Yoon, Hyung-Koo;Lee, Woo-Jin;Kim, Hyung-Sub
    • Journal of the Korean Geotechnical Society
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    • v.22 no.12
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    • pp.67-76
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    • 2006
  • The reasonable assessment of the shear stiffness of a dredged soft ground and soft clay is difficult due to the soil disturbance. This study addresses the development and application of a new in-situ shear wave measuring apparatus (field velocity probe: FVP), which overcomes several of the limitations of conventional methods. Design concerns of this new apparatus include the disturbance of soils, cross-talking between transducers, electromagnetic coupling between cables, self acoustic insulation, the constant travel distance of S-wave, the rotation of the transducer, directly transmitted wave through a frame from transducer to transducer, and protection of the transducer and the cable. These concerns are effectively eliminated by continuous improvements through performing field and laboratory tests. The shear wave velocity of the FVP is simply calculated, without any inversion process, by using the travel distance and the first arrival time. The developed FVP Is tested in soil up to 30m in depth. The experimental results show that the FVP can produce every detailed shear wave velocity profiles in sand and clay layers. In addition, the shear wave velocity at the tested site correlates well with the cone tip resistance. This study suggests that the FVP may be an effective technique for measuring the shear wave velocity in the field to assess dynamic soil properties in soft ground.

A Study on Various Soil Stiffness Evaluation Methods with Field Test (현장시험을 통한 다양한 지반강성 평가방법에 대한 연구)

  • Yoo, Wan-Kyu;Kim, Byoung-Il;Kim, Ju-Hyong;Park, Keun-Bo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.4
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    • pp.1373-1380
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    • 2010
  • The plate loading test(PLT) and the field density test are mainly used on the construction of embankments to control the compaction of a limited layer thickness. These two test methods are very time consuming and inefficient, but they are still commonly used as the methods of quality control for soil compaction. In the last 3 decades, many devices such as geogauge, light falling weight deflectometer(LFWD) and dynamic cone penetrometer(DCP) etc., have been introduced into the engineering market with the objective of acquiring in situ stiffness properties of the compacted soil layers. Recently, a new type of sensor, called compactometer, which in mounted on the drum of a roller and measures impact forces continuously with GPS, called as Continuous Compaction Control(CCC), has come into use in many countries such as America, Germany, Japan and so on. The main objective of this paper is to assess the potential use of these new devices as quality control and assurance devices for compacted soil layers. Based on this study, compactometer and the LFWD results werestrongly correlated with the result obtained from the PLT and the field density test.