• Title/Summary/Keyword: 제체의 안정성

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The Safety Assessment of Embankment by Three Dimensional Electrical DC Modeling (3차원 전기비저항 모델링을 통한 제체의 안정성 분석 연구)

  • Oh, Seok-Hoon
    • Journal of the Korean earth science society
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    • v.29 no.6
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    • pp.447-453
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    • 2008
  • Recently, the electrical DC survey has frequently been performed to assess the safety of embankment. This study showed that the damaged section of embankment could be appropriately detected by the survey only when the three dimensional effect was correctly considered. The shape of the three dimensional embankment was numerically implemented, and a proper modeling was performed to confirm the effect by analyzing the apparent and inverted true resistivity. Then, the field work was carried out. The three dimensional interpretation distinguished the erroneous weak zones from the geometrical artifact, and the embankment was ensured as safe both by the additional survey performed in rainy season and the partial excavation for direct observation.

Electrical Resistivity Response Due to the Variation of Embankment Shape and Reservoir Level (제체형태와 수위에 따른 전기비저항 반응 연구)

  • Oh, Seok-Hoon
    • Geophysics and Geophysical Exploration
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    • v.11 no.3
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    • pp.214-220
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    • 2008
  • The distortion effect of electrical response for two-dimensional (2-D) DC resistivity method was verified in terms of 2-D inversion result of synthetic data obtained by three-dimensional (3-D) modeling, which is frequently applied to assess the safety of center core-type fill dam structure. The distortion effect is due to 2-D interpretation for 3-D structure. By the modeling analysis, we found that the water level is correctly described in the resistivity section around the middle part rather than each end side of the embankment due to the 3-D terrain effect, when the material of the embankment is assumed as horizontally uniform. And when we set the slope of outer rock fill part as uniform. the sharper the slope of the center core is, the more similar the resistivity section reflects. On the other hand, when the slope of the rock fill is steep, the resistivity section shows the water level at lower position than the real one, and the 3-D distortion effect at the end side of the embankment was enhanced.

Sand Levee의 사면안정 해석

  • 최기봉;안병철
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2003.10a
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    • pp.207-213
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    • 2003
  • 본 연구는 양수발전 등을 목적으로 축조한 소형 Dam 및 Sand Levee의 수위가 급상승할 경우 제체의 내측면에 미치는 영향을 Bishop's simplified method를 사용하여 Seepage Force(침투력)의 항을 중심으로 분석한 것이다. 특히 침투력의 항은 제체의 사면경사가 급할 경우 및 수위의 상승속도에 따라 제체의 안전성에 많은 영향을 미친다.(중략)

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Analysis Wave Field on the Wave Pressure acting on the Frontal Slope of Rubble Mound Breakwater (경사식 방파제의 전사면 파압에 대한 파동장 해석)

  • 성상봉;전인식;이달수
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 2003.08a
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    • pp.98-102
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    • 2003
  • 지금까지 실무에서는 경사식 방파제 적정 단면 결정시 피복재 산정 및 설계파에 대한 파력을 산정하여 상치콘크리트 구조물의 안정성을 검토하는 것이 전부였다 하지만 현장에서 발생하는 상황은 더 많은 변수들이 작용하는 것을 보여 주고 있다. 예를 들면 파에 의하여 발생하는 투과파 및 월파로 제체의 내부 및 배면 석재의 이탈이 발생하는 경우는 익히 보아 왔던 일이지만, 반대로 월파가 발생하지 않았는데도 불구하고 제체의 침하와 배면의 석재에 이탈 즉 세굴이 발생하는 경우도 있다. (중략)

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The Study on the Simple Measurement by Using the Strain Gauge at Dam Dynamic Behavior Analysis (댐 거동 분석에서의 Strain Gauge를 이용한 단일 계측에 관한 연구)

  • Lee, Seungho
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.1
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    • pp.5-11
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    • 2007
  • Internal stress variation in the face slab concrete induced by reservoir water pressure may affect on the stability of the dam so that the reclamation type of strain gauge is applied for measuring internal stress variation. In this study, internal as well as external stress variation of dam was measured by using strain gauge that was reclaimed to the ${\circ}{\circ}$ dam. In the result, it was confirmed that other measurements by relevant gauges need to be supplemented as the use of strain gauge only is insufficient to evaluate the stability analysis and global behavior of the dam.

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Hydraulic & Hydrologic Design Criteria for an Emergency Discharge of Reservoir (I) (댐 비상방류 설계기준 선정을 위한 수리수문학적 검토(I))

  • Son, Kwang Ik;Yi, Jaeeung
    • Journal of Korea Water Resources Association
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    • v.48 no.3
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    • pp.149-158
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    • 2015
  • It is well known that emergency outlet works have to be provided for the safety of dams. However, concept of emergency outlet works did not applied for the design of the most dams in Korea. Korean design standard for low-level outlet works does not provide enough design criteria which could be used in design of emergency outlet works. In this research, as-built status and hydraulic design criteria of outlet works, such as drawdown rate or hydraulic pressure due to the impounded water depth, were examined. Another relationship between drawdown rate and the dam slope stability was also examined with SEEP model. It was found that 25% reduction of impounded water depth decreases the pressure forces about 50%. Therefore, outlet works should be designed to drawdown properly at the beginning of the emergency. Seepage analysis of dam bodies showed that most of Korean dams could safely stand for 1m/day drawdown rate. Higher drawdown rate could result high discharge so the drawdown rate must be related with the flood risk of downstream. Finally, multi-stage design was recommended that faster discharge for the initial 25% of water depth in 7-10 days than the rest of it in 1-2 months.

Safety Assessment of Embankment by Analysis of Electrical Properties (전기비저항 물성 분석을 통한 제체의 안정성 검토)

  • Oh, Seok-Hoon;Suh, Baik-Soo
    • The Journal of Engineering Geology
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    • v.18 no.3
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    • pp.245-255
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    • 2008
  • The variation of the electrical property of embankment material was analyzed from laboratory experiments and the result of field survey, in order to enhance the interpretation of electrical resistivity survey frequently used for safety assessment of embankment. At first, the kaolinite, showing similar physical property with core material of embankment, was used to examine the variation of the resistivity value according to degree of consolidation. The test showed that a drop of shear strength induces increase of resistivity value regardless of degree of water content. This result means that porous zones of weak core material in embankment may be appeared as highly resistive part in the electrical resistivity survey. This observation implies that it may fail to detect weak core material by electrical method, if we only try to and zones showing low resistivity value. And, we performed Standard Penetration Test (SPT) to analyze the correlation between electrical property and ground stiffness. Finally, a mechanism to describe the variation of electrical resistivity due to grouting effect was proposed and real field data were analyzed.

Reliability Analysis of Sloped-Coastal Structures with Sea-Level Rise (해수면 상승에 따른 경사식 해안 구조물의 신뢰성 해석)

  • Lee, Cheol-Eung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.1
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    • pp.42-48
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    • 2008
  • A system of risk assessment is developed by using the reliability analysis which evaluate quantitatively both stability and performance of sloped-coastal structures according to several scenarios of sea-level rise. By using reliability functions on armor unit and run-up, the probabilities of failure can be straightforwardly calculated with respect to several design parameters such as nominal diameter of armor unit, slope of coastal structure, and freeboard height. By comparing the results before and after sea-level rise, it may be possible to exactly assess some ranges of decrease of stability and performance of sloped-coastal structure with respect to sea-level rise. Therefore, it can also be possible to make a decision which parameters should be repaired or strengthened in order to maintain the original stability and performance of sloped-coastal structures. Finally, The present results may be useful for designing some kinds of new sloped-coastal structures including the effect of sea-level rise.

Evaluation of Applicability of HWAW (Harmonic Wavelet Analysis of Waves) Method in Determining Grouting Effect in Dam and Embankment (제체 그라우팅 효과 평가를 위한 HWAW방법의 적용성 평가)

  • Noh, Hee-Kwan;Park, Hyung-Choon
    • Journal of the Korean Geotechnical Society
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    • v.32 no.5
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    • pp.15-26
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    • 2016
  • Dam and embankment are very important civil structures. Grouting is widely used to repair and maintain dam and embankment, and it is important to evaluate the effect of grouting for dam safety. The non-destructive method based on determination of wave velocity in the dam or embankment is effectively used to evaluate grouting effect because wave velocity is identical with stiffness and grouting increases local stiffness in a dam. In this paper, HWAW (Harmonic wavelet analysis of waves) method was applied to evaluate the grouting effect. HWAW method can determine two-dimensional shear wave velocity map with good spatial resolution and the shear velocity profile by the proposed method is sensitive to a variation of stiffness of target system. Through numerical simulation and field tests, the applicability of HWAW method in determining grouting effect is shown.