• Title/Summary/Keyword: 측방변위

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Evaluation for Lateral Movements of Bridge Abutment on Soft Ground (연약지반상 교대측방이동에 대한 판정)

  • 홍원표;송영석;조용량
    • Journal of the Korean Geotechnical Society
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    • v.17 no.4
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    • pp.269-278
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    • 2001
  • 국내 30개의 교대측방이동 사례현장에 대하여 교대기초말뚝의 사면안정효과와 교대의 실측측방변위를 고려한 사면안정해석을 실시하였다. 해석결과 사면안전율은 말뚝의 효과를 무시한 경우 1.5이상, 말뚤의 효과를 고려한 경우 1.8이상 되어야 안전함을 알 수 있다. 그리고, 교대의 실측측방변위와 사면안전율과의 상관관계로부터 교대의 허용측방변위 설계기준은 5cm보다 1.5cm로 함이 더 합리적임을 알 수 있다. 사면안정해석결과와 교대의 실측측방변위를 토대로 기존에 제안된 교대측방이동 판정기준의 국내 적용여부를 검토한다. 이를 위하여 교대의 사면안정해석결과 및 실측측방변위와 교대측방이동 관련지수와의 상관관계를 조사한다. 그 결과 실측된 교대의 측방변위와 이를 고려한 사면안전율은 교대의 측방유동지수, 측방이동판정지수 및 지반의 안정계수와 무관한 경우도 많이 존재하는 것으로 나타났다. 이는 결국 이들 경험적인 지수만으로 교대측방이동을 판정하는 것은 불충분함을 의미한다. 따라서, 교대측방이동을 판정할 경우에는 반드시 교대의 측방변위를 고려한 사면안정해석이 실시되어야 한다.

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Stability of Bridge Abutments on Soft Ground Undergoing Lateral Flow (측방유동 연약지반상 교대의 안정성)

  • 홍원표;송영석;신도순;손규만
    • Journal of the Korean Geotechnical Society
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    • v.17 no.4
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    • pp.199-208
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    • 2001
  • 본 연구의 목적은 교대가 설치된 지반의 사면안전율과 교대측방변위의 관계를 분석하여 교대의 측방이동 판정기준을 마련하고자 함에 있다. 이를 위하여 국내의 연약지반에 설치된 30개 교대의 측방이동사례를 조사하고, SLOPILE (Ver 2.0)프로그램을 이용하여 교대의 측방변위와 교대기초말뚝의 사면안정효과를 고려한 사면안정해석을 실시한다. 해석결과 교대기초말뚝의 실측측방변위를 고려할 경우 1.8이상 되어야 한다. 또한, 교대기초말뚝의 허용측방변위량에 따른 사면안정 해석결과, 교대의 허용측방변위가 작게 규정될수록 사면안정성에 기여하는 말뚝의 효과는 감소하고 있음을 알 수 있다.

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Improvement of Medical Ultrasound Strain Image Using Lateral Motion Compensation (측방향 움직임 보상을 이용한 초음파 의료용 변형률 영상의 화질개선)

  • Park, Myung-Ki;Kwon, Sung-Jae;Jeong, Mok-Kun
    • The Journal of the Acoustical Society of Korea
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    • v.30 no.5
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    • pp.239-248
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    • 2011
  • In order to improve the quality of strain images in medical ultrasound imaging, displacements need to be accurately estimated. In this paper, in order to apply one-dimensional displacement estimation methods to two-dimensional motion estimation, the axial and lateral displacements are separately estimated. In order to estimate lateral displacements, one-dimensional signals aligned in the lateral direction are converted to analytic signals, which are then crosscorrelated. Strain images are produced by first compensating two-dimensional displacements for lateral motion with lateral motion displacement estimates obtained from the proposed lateral displacement estimation algorithm and then estimating axial displacements. Both phantom and human data experiments show that the proposed method provides better signal-to-noise ratio and contrast-to-noise ratio characteristics than a conventional strain imaging method that utilizes axial displacement estimates only.

A Study on Lateral Displacement of Caisson Constructed on Improved Ground (개량 지반에 설치된 케이슨의 측방변위에 대한 연구)

  • Kim, Myunghak;Lee, Sangwook;Yoon, Minseung;Han, Byungwon
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.4
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    • pp.33-41
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    • 2011
  • In case of building up port facilities on soft ground, unsymmetrical surcharge of embankment, which make the excess pore water pressure to increase, causes to occur lateral displacement due to plasticity of soil. A study on lateral displacement and settlement of the caisson, which is installed on improved ground, was accomplished. The field measurement data and calculated values obtained from FEM program of Plaxis were compared and analyzed. For numerical analysis, the properties of soils, constructions stage and time were considered. Lateral displacement was measured at the point of inclinometers installed in front of caisson. Settlement was measured at the center of extra embankment behind of caisson. Comparison of measured and calculated for lateral displacement showed that the calculated value was greater than the measured, and increasing trend was different. The calculated value showed step increasing as step extra embankment applied, whereas the measured gradually was increased. For settlement of embankment, the amount of both measured and calculated were similar, but the trend was different like that of lateral movement.

Case Study of Characteristics on Lateral Deformation in Soft Ground under Embankment in the Nakdong River Estuary(I) (낙동강 하구지역 성토하부 연약지반의 측방변형 특성에 관한 사례 연구(I))

  • Han, Byung-Won;Son, Hwa-Soo;Sung, In-Chool;Baek, Young-Gyun;Lee, Gay-Chun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.1178-1189
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    • 2010
  • 낙동강 하구지역 연직배수공법이 적용된 연약지반에서 성토시 발생할 수 있는 지반의 측방변형에 대해 3개소 현장 35개 지점에서 수행한 현장 계측데이터를 분석하였다. 성토과정에서 측방변형 패턴 및 변형량을 파악하는데 가장 우선적으로 파악해야 할 계측항목이 지중경사계이며 지반특성별 측방변형 패턴(최대 측방변위발생 지점, 전단변위 발생지점, 지층에 따른 변위발생 형태 등)의 정밀 분석을 위해서는 지중경사계가 설치된 지점의 지층구성을 파악하는 것이 가장 중요하다는 것을 알 수 있었다. 최대 측방변위량과 성토체 중앙부 침하량과의 관계에서는 Tavenas et al.(1979)이 제안한 ${\Delta}_y=(0.18+0.09){\Delta}_s$이하로 관측되었다. 또한 측방변형 억제 및 인접지반의 동반침하를 차단하기 위해 보강된 D.C.M., C.I.P.구간에서는 Tavenas et al.(1979)이 제안한 ${\Delta}_y=(0.18-0.09){\Delta}_s$이하로 관측되었다. 최대 측방변위량과 성토속도와의 관계에서는 과잉간극수압 소산에 필요한 충분한 시간과 원활한 배수가 될 수 있도록 시공관리(성토속도조절, 배수관리 철저)하는 것이 무엇보다도 중요하다는 사실을 다시 한 번 확인 할 수 있었다. 마지막으로 편재하중 재하에 따른 인접 지반 및 구조물의 침하 및 기울기 변화는 측방유동에 의한 거동과 함께 압밀침하에 의한 제체의 체적감소로 인한 인접지반의 동반침하가 상당기간 동안 발생하고 있는 것으로 관측되었다.

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Comparisons of Empirical Methods with Numerical Analysis on Lateral Flow in Soft Soils (측방유동에 관한 경험식 및 수치해석의 비교)

  • Kim Dae-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.4
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    • pp.665-670
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    • 2006
  • In this paper, the results of empirical methods and the numerical analysis were compared and investigated on the lateral displacement due to embankment in soft soil. The empirical methods gave different results so the possibility of lateral displacement could not be determined only by the empirical methods. The numerical analysis could be used so effectively that its result showed useful lateral and vertical displacements with depth and distance.

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Study on Lateral Flow of Soft soils by Field Measurement and Numerical Analysis (계측 및 수치해석에 의한 연약지반의 측방유동 연구)

  • Kim Dae-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.6 no.5
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    • pp.423-427
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    • 2005
  • In this paper, the lateral displacement of soft soil was measured in pier structure. The result was compared and investigated with the result of numerical analysis. The lateral displacement of soft soil was affected by lateral flow of soft soil due to embankment rather than settlement, and rapidly occurred at the embankment and preloading phases. The measurement and the numerical analysis showed very similar trend of lateral displacement but the magnitude was larger in numerical analysis than in measurement.

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Application of Probabilistic Neural Network (PNN) for Evaluating the Lateral Flow Occurrence on Soft Ground (연약지반의 측방유동 평가를 위한 확률신경망 이론의 적용)

  • Kim, Young Sang;Joo, No Ah;Lee, Jeong Jae;Lee, Sook Ju
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.1C
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    • pp.1-8
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    • 2008
  • Recently, there have been many construction projects on soft ground with growth of industry and economy. Therefore foundation piles of abutments and(or) buildings had been suffering from a lot of stability problems of inordinary displacement due to lateral flow of soft ground. Although many researches about lateral flow have been carried out, it is still difficult to assess the mechanism of lateral flow in soft ground quantitatively. And reasonable design method for judgement of lateral flow occurrence in soft ground is not established yet. In this study, six PNN (Probabilistic Neural Network) models were developed according to input variables and database compiled from Korea and Japan for the judgment of lateral flow occurrence. PNN models were compared with present empirical methods. It was found that the developed PNN models can give more precise and reliable judgment of lateral flow occurrence than empirical methods.

A case study on the lateral movement of bridge abutment foundation and repair methods (교대의 측방변위와 대책공법에 대한 사례연구)

  • Lee, Byung-Suk;Lee, Jae-Yeol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.3
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    • pp.1359-1369
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    • 2012
  • In the case of using pile foundation to support bridge abutments on soft ground, the soft ground often causes serious troubles such as lateral movement of bridge abutments by lateral surcharges. In this paper, we investigated and measured the amount of strain of a bridge abutment in the south-western part of Korea. To check the stability and possibility of lateral movement of the bridge abutment, we used the four analysis methods and compared those results; lateral movement index, index for decision of lateral movement and infinite element analysis method. We performed soil and ground tests to fine the causes of the strain and lateral movement. After reviwing several types of repair methods, we suggested the anker reinforcement method along with surcharge process method as a proper repair and rehabilitation of the bridge abutment. Our investigation by through the infinite element analysis method confirmed the effectiveness of the anker reinforcement method allong with the surcharge process method.

Lateral Displacement and Ground Rising Movement with Soil Embankment (성토에 따른 지반의 측방변위와 지표면 융기량)

  • Jeong, Ji-Cheol;Shin, Bang-Woong;Oh, Se-Wook
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.2
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    • pp.63-69
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    • 2004
  • During and after the construction of embankment on soft ground, consolidation settlements and lateral displacements develop. But generally it's very difficult to predict the magnitude of lateral deformations and the correct distribution of lateral displacements with depth under the toe of embankment because the consolidation and the shear deformations of soft ground occur simultaneously. This study shows that later displacements of ground surface arise by embankment loading act on soft clay hight water contents in laboratory model testing. The results of model test are observed settlement of embankment, amount of maximum rising and displacement of ground surface with loading velocity. The formula were proposed to predict lateral movement by test series.

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