• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.39-44
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• 2003

Centrifuge test was conducted to simulate the effects of consolidation settlement of capped contaminated marine sediment. A fluorescent dye was used to monitor the movement of pore water through the cap layer. Dye tracer study clearly showed the consolidation induced advective transport of contaminants. Thus, the capping layer must be appropriately designed to reduce the effects of consolidation induced advective transport. The results from the centrifuge test were compared to predictions made by the Primary consolidation, Secondary compression, and Desiccation of Dredged Fill (PSDDF) computer program, which can qualitatively estimate the consolidation settlement of capped marine sediment. Although PSDDF approximated closely the secondary compression in the centrifuge test (i.e., compare data points from 18 to 25 prototype years), the maximum deviation between centrifuge test result and PSDDF prediction was 20 % about prototype time 6 years. Thus, designers should utilize PSDDF consolidation settlement results with caution.

• Journal of the Korean Geotechnical Society
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• v.26 no.9
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• pp.25-35
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• 2010

Settlement at reclamation area caused by secondary compression should be considered using spatial evaluating method because the thickness of consolidation layer varies at every location. Probabilistic method can be implemented to evaluate uncertainty of spatial distribution of secondary compression. This study spatially evaluated mean and standard deviation of secondary compression in the overall analyzing region using spatial distribution of consolidation thickness estimated by ordinary kriging method and statistical values of soil properties. And then, the area where secondary compression exceeds a design criterion at the specific time was evaluated using probabilistic method. It was observed that the area exceeding the design criterion increased as the variability of $C_{\alpha}/(1+e_o)$ increased or the probabilistic design criterion 0: decreased. It is considered that the probabilistic method can be used for the geotechnical design of soft ground when a probabilistic design criterion is established in the specification.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.644-651
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• 2006

An application of concrete track is being actively processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance ire, but is very difficult system to maintain after earthwork settlement occurred. Therefore, the management and control of embankment and foundation settlement is very important for the successful concrete track construction. We expect that the main part of the settlement of the concrete track is the one of embankment and foundation supporting it. Settlements vulnerable to the concrete track among the causes of lots of settlements are primary consolidation and secondary compression settlement of foundation, creep settlement of embankment, settlement caused by train load, and unequal settlement resulting from the difference of embankment material and construction process. This paper investigated the settlement causes to make badly effects on the concrete track and also evaluated the settlement with field tests and numerical analysis.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.1-8
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• 2016

The purpose of this study is to examine the consolidation characteristics of waste landfill from sodium carbonate production. The waste lime is a byproduct from the production of soda ash. The consolidation settlement of waste lime landfill was determined for waste lime specimen which obtained from the field boring. The consolidation tests are conducted for determination of the primary and secondary consolidation settlements. The waste lime is classified as an organic soil with high plasticity. As a result of an organic content test, the contents of organic matter in waste lime is much higher than that of normal clay. Finally, the total consolidation settlement of waste lime landfill is calculated by using a theoretical method and computer program for the given initial void ratio, compression index, and embankment height.

• Journal of the Korean Geosynthetics Society
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• v.23 no.1
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• pp.39-47
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• 2024

In this study, physical property tests and standard consolidation tests were conducted on the marine clay of Busan New Port and North Port, the middle and lower reaches of the Nakdong River including Gimhae and Yangsan, and Ulsan regions. The moisture content, a property unrelated to sample disturbance with small individual test errors, was used for regression analysis with the compression index, virgin compression index, consolidation coefficient, expansion index, and secondary compression index, among others. Subsequently, the correlation and accuracy were evaluated. Upon analyzing the correlation between the moisture content, void ratio, and liquid limit commonly used physical properties for calculating compression indexes, it was confirmed that the liquid limit had the lowest correlation. Through a linear regression analysis of the consolidation constants using the current moisture content in the natural state, a high correlation was demonstrated. Relationship equations were then presented to determine settlement and settlement time. This study suggests that moisture content can be utilized as an alternative for evaluating and calculating consolidation constants when examining ground settlement in sedimentary clays distributed in the Busan and Gyeongnam regions.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.192-197
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• 2004

폐기물 매립층의 침하는 매립 폐기물의 조성특성의 영향으로 인하여 침하특성이 일반 흙의 토질역학적 거동과 다르게 나타난다. 폐기물의 침하특성은 매립당시 나타나는 폐기물 하중에 의한 침하특성과 향후 장기적으로 유발되는 생화학적 침하특성을 구분하여 규명하는 것이 필요하다. 본 연구에서는 국내 대표적 매립지 폐기물 침하에 대한 계측자료를 바탕으로 역학적 일차 압축침하와 생화학적 이차 압축침하에 대한 침하특성계수를 산정하였다. 또한 Sower(1973)의 매립지 폐기물에 대한 침하량 산정식을 응용하여 다단형 매립지 폐기물에 적용할 수 있는 침하량 산정식을 구성하였다.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.110-115
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• 2011

Numerouslong-term consolidation and secondary compression settlements may occur in Busan clay, which is astructured soft clay and consists of a thick clay deposit. As a surcharge load is applied to soils, soils experience different stress paths with depth. Therefore, it is necessary to study the long-term consolidation behavior of Busan clay considering stress conditions such as OC or NC states. In this study, a series of long-term consolidation tests were performed to investigate the consolidation characteristics of Busan clay for 20 days. The undisturbed clay samples were taken from 3 sites located in the Nakdong River estuary. The results showed that the creep rate of the Busan clay gradually decreased with time, which indicated that the secondary compression settlement decreased with time. In addition, the experimental results for 3 samples showed that the ratios were about 0.0363 and 0.051, respectively.

• Journal of the Korean Geotechnical Society
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• v.36 no.5
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• pp.17-24
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• 2020

In order to analyze the effect of applying the bioreactor landfills on the waste landfill for acceleration of waste biocompression, a settlement experiment was performed. The secondary compression indices (C_α) were analyzed, and compared with the results of experimental studies conducted in other countries. Analyses of C_α from the experiment showed that the recirculation method of mixing leachate and FWL could accelerate the waste settlement as much as 2.9 times and 2 times more than the leachate recirculation and the sanitary landfills due to additional biocompression generated by the organic matter in FWL. The C_α in this study was smaller than the C_α of the other studies due to the low organic content of the waste in accordance with domestic waste policies to reduce food waste. The relation between biodegradable waste content and C_α was analyzed. The C_α of the waste was shown to be sensitive to biodegradable waste content, and become higher as the content of the biodegradable waste increases.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.5
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• pp.133-139
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• 2003

Dredged soil from sea has much higher water content than liquid limit of clay and even if small loads apply, it will suffer a great settlement. Therefore it is very difficult to perform a consolidation test with general consolidation apparatus because of high water content. In this study Rowe Cell Apparatus consolidation tests have been performed with 1 remolding clay of water content 56% and 4 slurry clays of a water content of 100%, 120%, 133% and 150%. From the test results the consolidation characteristics such as compression index, secondary compression index and consolidation coefficient have been investigated with a variation of water content of dredged soil. The equations to get consolidation constants such as a compression index, a consolidation coefficient have been proposed with the field water content.

• Geotechnical Engineering
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• v.10 no.4
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• pp.167-180
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• 1994

A series of long term consolidation tests were conducted under loading -unloading and loading(pc) -unloading(p.) -reloading(p,) conditions using reconstituted clay in order to investigate the effect of stress history on secondary consolidation characteristics and the applicability of the secondary consolidation model suggested by Bjerrum to overconsolidated clays. According to the test results, the secondary compression settlement affected by the stress history in the first half of experimental period and the coefficient of secondary compression, C‥‥ is dependent on overconsolidation ratio, OCR(p,1 p.), maBium OCR (p./p.), and unloading duration time. Moreover the coefficient of secondary consolidation in the latter half of experimental period Cn is mainly affected by OCR and it gradually reduces with OCR increment. Finally the comparison of the experimental results with the Bjerrum model indicates that the Bjerrum model can be applied beyond certain range of stress history in the overconsolidated clay.