• Title/Summary/Keyword: Marine upheaval soil

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Chemistry of Strong Acidic Soil on Ulsan-Jungjadong Cut-Slope Affecting Seed Germination (종자발아에 영향을 미치는 울산 정자동 절토비탈면 강산성 토양의 화학적 특성)

  • Jang, Chang-Hee;Kim, Min-Soo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.9 no.6
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    • pp.133-142
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    • 2006
  • Occasionlly, a lot of plants withered on the marine upheaval soil, because of the potential acid sulfate soil. It was necessary to investigate the chemistry of soil, before planting on Ulsan-Jungjadong cut-slope of road construction site. Cut-slope surface soils were sampled on the every varying points in soil colour and analyzed chemically. Germination status of seeds in sample soils was investigated such as Albizzia julibrissin, Festuca arundinacea. Relationship between germination status and chemistry of soil was analyzed. The results of investigation and analysis are as follows. 1. Germination of seeds was inhibited, less than pH($H_2O$ 1 : 5) 2.63. 2. Germination of seeds was inhibited, more than EC($H_2O_2$ 1 : 5) 13.4mS. 3. Germination of seeds was inhibited, more than aluminum ion content 2.0ppm in soil solution extracted by A$H_2O$ and 6.2ppm by $H_2O_2$. 4. pH($H_2O$ 1 : 5), EC($H_2O_2$ 1 : 5) and aluminum ion content proved chemical indicators of seed germination inhibition, in case of potential acid sulfate soil.

A Study on the Buckling Stability due to Lateral Impact of Gas Pipe Installed on the Sea-bed (해저면에 설치된 가스관의 외부충격에 의한 좌굴 안전성 검토)

  • Park, Joo-Shin;Yi, Myung-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.2
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    • pp.414-421
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    • 2022
  • Subsea oil and gas exploration is increasingly moving into deeper water depths, and typically, subsea pipelines operate under high pressure and temperature conditions. Owing to the difference in these components, the axial force in the pipe is accumulated. When a pipeline is operated at a high internal pressure and temperature, it will attempt to expand and contract for differential temperature changes. Typically, the line is not free to move because of the plane strain constraints in the longitudinal direction and soil friction effects. For a positive differential temperature, it will be subjected to an axial compressive load, and when this load reaches a certain critical value, the pipe may experience vertical (upheaval buckling) or lateral (snaking buckling) movements that can jeopardize the structural integrity of the pipeline. In these circumstances, the pipeline behavior should be evaluated to ensure the pipeline structural integrity during operation in those demanding loading conditions. Performing this analysis, the correct mitigation measures for thermal buckling can be considered either by accepting bar buckling but preventing the development of excessive bending moment or by preventing any occurrence of bending.