• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.993-998
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• 2009

This study was conducted to propose the model that is able to predict long-term settlement of sands containing carbonates. We can observe that in addition to the initial elastic compression, a considerable additional compression occurs with long-term period in some sands. The compressibility of sands is significantly dependent on particle characteristics. Some sands have many pores and particularly has an angular shape. To predict of long-term settlement of these sands which contain carbonates, first of all a variety of tests which are to assess chemical, physical and compression characteristics of these sands were conducted. Second, in order to know settlement with time, the time parameter was determined by analyzing the measured data obtained from $\bigcirc\bigcirc$ area. The measured settlement of this area shows that in addition to the initial elastic compression, a considerable additional compression occurring with time. It was caused by the crushing, shattering, and rearrangement of particles, which were real phenomena in sandy soils under loading condition. Based on this case study, we proposed that a simple method is able to predict settlement with time of sandy soil containing carbonates.

• 한국농공학회지
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• 제39권3호
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• pp.128-137
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• 1997

In this study, examined influence of consolidation effect that had affected by location of pump inlet that was set collection well for drainage of pore water discharged by embankment on soft ground through the field test. The results of this study are summarized as follows; 1 Initial consolidation curve value were larger than theoritic value, the cause of these phenomena were thought influence of secondary consolidation and three dimensional strain of soft clay. 2. The settlement value of Hosino method was larger than that of Hyperbolic method, but settlement value of Hyperbolic method was accurate more than that of Hosino method in the prediction of settlement. 3. When pump inlet in collection well came down from GL+O.3m to GL-1.5m, settlement value increased about 10cm and when the ground water level was made insitu after pumping had completed , settlement was expanded about 7~8cm. So it is found that location change of pump inlet bad an influence on settlement remarkably. 4. If location of pump inlet in collection well for large scale estate or wide road site is lowered than original ground level, the settlement will be accelerated effectively, and at this stage automatic pump must be used in pumping.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1712-1716
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• 2008

Performance of ground improvement project using prefabricated vertical drains of condition, in which approximately 10m dredged fill overlies original soft foundation layer in the coastal area has been conducted. From field monitoring results, excessive ground settlement compared to predicted settlement in design stage developed during the following one year. In order to predict the final consolidation behavior, recalculation of consolidation settlements and back analysis using observed settlements were conducted. Field monitoring results of surface settlements were evaluated, and then corrected because large shear deformation was occurred by construction events in the early stages of consolidation. To predict the consolidation behavior, material functions and in-situ conditions from laboratory consolidation test were re-analyzed. Using these results, height of additional embankment is estimated to satisfy residual settlement limit and maintain an adequate ground elevation. The recalculated time-settlement curve has been compared to field monitoring results after additional surcharge was applied.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2004년도 학술발표논문집
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• pp.52-52
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• 2004

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 준설 및 환경매립에 관한 학술세미나
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• pp.51-81
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• 1999

• Geomechanics and Engineering
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• 제30권4호
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• pp.325-336
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• 2022

This paper analyzes the ground surface settlements induced by side-by-side twin shield tunnels bored in sedimentary soils, which primarily consist of sand with clay strata above the tunnel crown. The measurements were obtained during the construction of twin tunnels underneath the Incheon International Airport (IIA) located in Korea. The measured surface settlement troughs are approximated with Gaussian functions. The trough width parameters i and K of the settlement troughs produced by the first and second tunnel passings are determined, along with those for the total settlement trough. The surface settlement troughs produced by the first shield passing are reasonably represented by a symmetric Gaussian curve. The surface settlement troughs induced by the second shield tunnel display marginal asymmetric shapes at selected sections. The total settlement troughs are fitted both with a shifted symmetric Gaussian function and the superposition method utilizing an asymmetric function for the incremental trough produced by the second tunnel. It is revealed that the superposition method does not always produce better fits with the total settlement. Instead, the shifted symmetric Gaussian function is overall demonstrated to provide more favorable agreements with the recordings. Therefore, the shifted symmetric Gaussian function is recommended to be used in the design for the prediction of the settlement in clays caused by twin tunneling considering the simplicity of the procedure compared with the superposition method. The amount of increase in the width parameter K for the twin tunnel relative to that for the single tunnel is quantified, which can be used for a preliminary estimate of the surface settlement in clay induced by twin shield tunnels.

• 한국지반공학회논문집
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• 제15권5호
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• pp.99-110
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• 1999

선행하중공법이 실시되는 낙동강 삼각주에서 체계적인 지반조사를 통하여 침하량과 압밀소요 시간이 예측되었으며, 엄선된 각종 계측기를 이용하여 현장계측이 수행되었다. 비교결과, 약20m 두께의 모래층에 대하여 예측침하량은 실측치의 20%에 불과하였다. 이러한 과소평가의 원인은 PBD타입시의 진동, 시간의존적 침하 및 탄성계수의 과대평가 등에서 비롯되었다. 모래층 아래에 위치한 약 20m 두께의 점성토층이 미압밀상태에 있는 것으로 가정하였던 이유 때문에 예측침하량은 실측치에 비하여 약240%까지 과대평가되었다. 그러나 압축곡선을 재구성하고 정규압밀점토를 위한 압밀침하공식을 적용하였을 때 재계산된 침하량은 실측값에 비교적 비슷하였다. 그리고 압밀소요시간은 각종 영향인자로 인하여 실제값에 비하여 약45% 과소평가되었다.

• 한국지반공학회논문집
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• 제23권6호
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• pp.85-95
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• 2007

본 연구에서는 버티칼 드레인으로 개량된 점성토 지반의 잔류침하 예측법을 제안하기 위하여 모델지반에 대해 탄-점성 압밀이론을 이용한 일련의 수치해석을 행하였다. 그리고 수치해석을 통하여 정규압밀영역에 대해 유효반경비, 압밀압력의 영향과 버티칼 드레인에 의한 3차원압밀에 있어서의 잔류침하를 감소시키기 위한 과압밀영역에서의 과압밀비의 영향을 조사하였다. 또한, 모델지반의 수치해석결과에 기초하여 버티칼 드레인 타설지반의 잔류침하 예측법과 잔류침하를 허용치 이내로 제어하기 위해 필요한 과압밀비의 결정법을 제안하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.383-395
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• 2007

As a state-of-the-art paper related to consolidation settlement, the 31th Terzaghi lecture was briefly described. Case histories that are compared between predicted and measured settlements in the Nakdong River deltaic plane were introduced to show the true picture of our technology. Structures and other features of clays in this country were needed to understand, which are closely related to sample disturbance and also consolidation properties. In order to improve the settlement-related technology, some problems that we have faced and their alternatives were considered.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.349-354
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• 2005

In this study, settlement characteristics of 23 CFRD was investigated from monitoring data and the method to estimate the crest settlements considering internal settlement during constructions was proposed. Moreover, crest settlement smaller than 20cm and deflection of face slab smaller than 20cm are not considered to be critical to the stability of large dam whose height is over 40m. Therefore, we assigned the region as safe zone that can be used as a guideline of maintenance of dam. These estimated data can be used in the design, construction and long-term maintenance in domestic CFRD hereafter.