• Title/Summary/Keyword: average index of difference in settlement

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Relative Settlement Analysis of Soft Ground (연약지반의 상대적 침하 거동 분석)

  • Young-Jun Kwack;Heui-Soo Han
    • The Journal of Engineering Geology
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    • v.33 no.2
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    • pp.229-240
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    • 2023
  • Instruments are installed in soft ground improvement projects to manage economic and safe construction. When analyzing data, the amount of settlement data over time can be used to understand the overall ground settlement behavior, but it is difficult to analyze the interrelatedness between measurement points. Therefore, to analyze the relative compressive settlement behavior between measurement points, the settlement amount and velocity were processed and defined as the mean settlement difference index (ASi,j) and the slope difference index (SDIi,j). Plotted in the mean settlement difference index - slope difference index (ASi,j-SDIi,j) coordinate system. As a result of the analysis of the relative compaction subsidence behavior between the measuring points, the relationship between the measuring points in the average subsidence difference index - slope difference index coordinate system moved to area 1 as the compaction was completed. By continuously plotting the movement path of the observation point in the corresponding coordinate system, the relative settlement behavior between the measurement points was analyzed, and it was possible to check whether the settlement behavior of the two measurement points was stable or unstable depending on the direction of the path.

Analysis of Relative Settlement Behavior of Retaining Wall Backside Ground Using Clustering (군집분류를 이용한 흙막이 벽체 배면 지반의 상대적 침하거동 분석)

  • Young-Jun Kwack;Heui-Soo Han
    • The Journal of Engineering Geology
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    • v.33 no.1
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    • pp.189-200
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    • 2023
  • As urbanization and industrialization increase development in downtown areas, damage due to ground settlement continues to occur. Building collapse in urban has a high risk of leading to large-scale damage to life and property. However, there has rarely been studied on measurement data analysis methods when uneven loads are applied to the excavated ground and no prior knowledge of the ground. Accordingly, it was attempted to analyze the relative settlement behavior and correlation by processing the time-series surface settlement of construction sites in the urban. In this paper, the average index of difference in settlement and average of relative difference in settlement are defined and calculated, then plotted in the coordinate system to analyze the relative settlement behavior over time. In addition, since there was no prior knowledge of the ground, a standard to classify the clusters was needed, and the observation points were classified into using k-means clustering and Dunn Index. As a result of the analysis, it was confirmed that all the clusters moved to the stable region as the settlement amount converges. The clusters were segmented. Based on the analysis results, it was possible to distinguish between the independent displacement area and same behavior area by analyzing the correlation between measurement points. If possible to analyze the relative settlement behavior between the stations and classify the behavior areas, it can be helpful in settlement and stability management, such as uplift of the surrounding area, prediction of ground failure area, and prevention of activity failure.

A Numerical Study on the Effects on Consolidation Settlement Behavior due to Uncertainty of Compression Index (압축지수의 불확실성이 압밀침하 거동에 미치는 영향에 대한 수치적 평가)

  • Byun, Yoseph;Kim, Kwangyoon;Lee, Changki;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.11
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    • pp.43-50
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    • 2012
  • In this research, the value of consolidation index was investigated. The range of the investigated standard deviation was analyzed and the deviation based settlement was calculated. Also, the compression index, which is the effect of the uncertainty in the ground was analyzed using the flimsy ground construction method. The settlement behavior in each embankment compaction stage was analyzed by applying the precompression load method, drainage expediting method, and displacement method through numerical analysis. In addition to the above, the settlement behavior was studied by analyzing the Piled Raft method which is stable for long term settlement. As a result, the final settlement amount based on average analysis results was that the settlement based on each of the average interpretation value, mean value of the maximum and minimum value and average compression index was different. The result of the comparison shows the difference in variation coefficient by the difference in time. Amongst them, the Piled Raft method shows the most consistent variation coefficient regardless of time and it also was least affected by the compression index of uncertainty.

A study on the relationship between engineering properties and compression index for Nakdong-River estuary clay (낙동강하구 점토의 공학적 특성과 압축지수와의 상관성 연구)

  • Jin, Seung-Hyeon;Lee, Kyu-Hwan;Jung, Dae-Suk
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.737-742
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    • 2009
  • This research intends to clarify the engineering characteristics of compression index which plays the most important role in the calculation of consolidation settlement, based on the survey of the clay in the estuary of Nakdong River. In addition, it will analyze the parameters of soil and the correlation between the parameters and the existing relation, especially the correlation with compression index, through which it will propose a proper relation for the parameters of clay in this area. As a result of the study, the relation between the settlement and the compression rate using compression index showed 13% settlement error on the average. It is judged that this number can be used for forecasting the consolidation characteristics and the settlement for brief (preliminary) design when the difference between the execution settlement and the measuring settlement is regarded to be 15%.

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