• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.51-58
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• 2008

The George Massey immersed tunnel passes the Fraser River near Vancouver, Western Canada. In this paper, dynamic analysis of the tunnel on sandy soils was performed using an effective stress constitutive model called UBCSAND. This model is able to calculate pore pressure rise and resulting tunnel deformation due to cyclic loading. Centrifuge tests conducted at RPI are used to verify the model performance. Centrifuge tests consist of 3 models: Model 1 is designed for an original ground condition, Model 2 for a ground improvement by compaction method, Model 3 for a ground improvement by gravel drainage. The results of centrifuge Model 1 are presented and compared with predictions of UBCSAND model. This model well captured the results of centrifuge test and therefore can be used to predict dynamic behavior of similar tunnels or underground structures on sandy soils.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.685-692
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• 2000

Vertical drain used improvement soft clay is made of not only decreasing construction time but also increasing the ground strength during some decades. As, it is applied to improvement soft clay with vertical drain, it is designed by the result that is caused by oedemeter test ignored anisotropic of the ground related to consolidation conditions. When we are expected consolidation conditions, the most important factors is soil of compaction and water permeability. Above all, anisotropic of the ground permeability show the results which differ between vertical and radial drainage. Recently, We study for radial consolidation coefficient and permeability coefficient that utilized Rowe Cell Consolidation and permeability tester but, it dont use well because of not only a supply lack also difficulty of test. The paper experimented with searching anisotropic of the ground so there are Rowe Cell test, standard consolidation tester and modified standard consolidation test that have pohang's soft clay ground. Therefore, we find anisotropic of the ground and a tester of easy use more than before. We made a comparison test result between the devised tester and Rowe Cell tester, Also, we learned average degree of consolidation for partial penetrating vertical drains. We were found relations as effective stress-void and effective stress-permeability coefficient through those tests.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1240-1249
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• 2008

Jacket anchor was developed to increase the pullout resistance of general ground anchor in soft ground, and the mechanism of pullout resistance of jacket anchor was analyzed. Also, the ultimate bond stress of jacket anchor was estimated by ultimate resistance which is determined by field tests. Grout milk was injected into the jacket to make grout bulb of jacket anchor. The formation of grout bulb of jacket anchor increases the diameter of grout bulb, ground strength and confining pressure between anchor grout and soil. From the twelve field test results, it was observed that the pullout resistance of jacket anchor is 15.38~295.02%(average 83.53%) greater than that of general ground anchor, and plastic deformation of jacket anchor is 20.78~1,496.45%(average 288.78%) smaller than that of general ground anchor at the same load cycle. Especially, it was investigated that the increase of ultimate resistance over 200% and the reduction of plastic deformation over 600% was obtained in gravel layer. It means that the jacket anchor is superior to the general ground anchor in gravel layer. Finally, the ultimate bond stress was proposed to design jacket anchor.

• 한국조경학회지
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• 제33권6호
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• pp.40-50
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• 2006

This study was carried out to examine the tree-ring growth characteristics of Zelkova serrata Makino after replanting, for the built-up planting founds for stability of landscaped trees in the reclaimed land from the sea. the factors, many affecting the growths of Zelkova serrata Makino, were the replanting stress and drought. The growth reduction due to replanting and drought occurred in the replanting year and the following year. The mean sensitivity(year-to-year variation) and the coefficient of variation(tree-to-tree variation in a certain year) in tree rings of Zelkova serrate Makino, were higher in the poor soil sites than in the favourable soil ones. And the poor soil sites were the filled ground of improve soil and the covered ground of improve soil and the top ground of big mounding than mounding ground sites, especially soil hardness, alkali soil, high $Na^+\;and\;K^+,\;low\;Ca^{++}\;and\;Mg^{++}$ and T-C were the most crucial. We suggest technique development of the built-up planting ground for stability in the reclaimed land from the sea. The built-up planting grounds in reclaimed land from the sea, should be considered for the use of fair soil with the physical and chemical soil properties, -high level foundation of planting ground, and the prevention of disturbed soil-.

• 한국산학기술학회논문지
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• 제13권7호
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• pp.3216-3223
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• 2012

심층혼합처리(deep cement mixing, DCM)공법은 두꺼운 연약지반을 개량하는 공법 중 하나이다. 이 공법은 저소음, 저진동으로 공해가 적고 단시간에 큰 강도를 얻을 수 있는 장점이 있다. DCM공법과 같이 연약지반 개량 후 복합지반이 형성되는 지반의 침하량 산정을 위해서는 응력분담비의 결정이 필요하다. 이 연구에서는 DCM공법으로 개량된 복합지반 거동특성을 이해하기 위하여 모형재하시험을 실시하였다. 모형시험에서 측정한 토압과 침하량, 그리고 기존 제안도표를 이용하여 응력분담비를 산정하였는데 응력분담비는 각각 35.4, 28.6, 27.02로 DCM 개량체에 큰 응력집중이 발생하는 것으로 나타났다. 이러한 결과는 기존 연구결과에 의한 응력분담비(26.52, 32.5)와 비교할 때 유사한 값을 갖는 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.334-344
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• 2007

This paper performed a comprehensive evaluation of the results of the 2007 Ground Response Analysis Round Robin Test, at which 14 institutions and individuals participated. The submitted results showed significant discrepancies. The main reason for this difference has been attributed to the dispersion in the estimated shear wave velocity profiles and dynamic soil curves. It is therefore concluded that accurate evaluation of the material properties is of primary importance for reliable estimation of the ground vibration. Evaluation of the effect of the analysis method showed that the equivalent linear analysis overestimates the peak ground acceleration, but overall the results are similar to a total stress nonlinear analysis. However, the total and effective stress nonlinear analyses show distinct discrepancies, the effective stress analyses consistently resulting in a lower response due to the development of the excess pore water pressure and thus softer response.

• 한국지반공학회논문집
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• 제22권4호
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• pp.21-30
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• 2006

본 연구에서는 조립질 말뚝으로 개량된 점토지반의 지지력, 응력분담비, 말뚝 및 지반의 변형형태를 파악하기 위하여 말뚝의 종류(CSCP, SCP)와 치환율(0, 20, 40, 60%)을 변화시키면서 원심모형실험을 수행하였다. 실험결과, CSCP와 SCP로 개량된 지반의 하중비는 치환율이 증가함에 따라 비례적으로 증가하였고, CSCP로 개량된 지반의 평균 지지력비가 SCP로 개량한 경우보다 $8{\sim}21%$ 정도 크게 평가되었다. CSCP로 개량된 지반의 평균 응력분담비가 SCP보다 크게 나타나 CSCP가 더 큰 응력을 부담하는 것으로 평가되었다. CSCP로 보강된 지반에서는 팽창파괴가 발생하였고, SCP로 보강된 지반에서는 팽창 및 전단파괴가 동시에 발생하였다.

• 산업기술연구
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• 제22권B호
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• pp.211-218
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• 2002

The paper is to show the behavior of composit ground which is installed with sheet pile in soft soil improved by sand compaction pile. The results of load-settlement relationship, earth pressure, stress concentration characteristics, and final water content were obtained by centrifuge model test. Two cases of tests, installation of sheet pile on the corner and both side of the loading plate for the improved SCP ground which was designed twice of the footing width, were performed for the tests under the vertical and horizontal loading and both side of corner. Finite element program(CRISP) for sand compaction pile using elasto-plastic model and numerical analysis for soft soil using modified cam-clay constitutive equation were compared and analized with the results of model tests. The result of analysis show the increased bearing capacity of soil after, SCP and sheet pile was installed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.327-334
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• 2008

This paper presents the results of investigation on the influencing factors for GESC(Geogrid-Encased Stone Column) method in soft ground. A parametric study was then conducted on the influencing factors such as replacement ratio, geogrid stiffness and thickness of soft ground using stress-porepressure coupled analysis. The results indicate that the relationship between these parameters and settlement ratio, and the relationship between these parameters and stress concentration factor can be identified.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.415-424
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• 2004

This paper presents the effect of groundwater on tunneling performance. The interaction between the tunneling and groundwater was examined using a 3D stress-pore pressure coupled finite-element analysis, The results of the 3D coupled analysis were then compared with those of a total stress analysis. Examined items included pore pressures around lining and lining forces. Also examined include face displacements and ground surface movements, The results indicated that the interaction between the tunneling and ground water significantly increases the lining forces and ground deformations, and that the effect of ground water on tunneling can only be captured through a fully coupled analysis, Implementations of the findings from this study arc discussed in great detail.