• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.987-997
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• 2008

Successful design, construction and maintenance of geotechnical structure in soft ground and marine clay demands prediction, control, stability estimation and monitoring of settlement with high accuracy. It is important to predict and to estimate the compression index of soil for predicting of ground settlement. Lab. and field tests have been and are indispensable tools to achieve this goal. In this paper, Artificial Neural Networks (ANNs) model with Levenberg-Marquardt Algorithm and field database were used to predict compression index of soil in Korea. Based on soil property database obtained from more than 1800 consolidation tests from soils samples, the ANNs model were proposed in this study to estimate the compression index, using multiple soil properties. The compression index from the proposed ANN models including multiple soil parameters were then compared with those from the existing empirical equations.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.376-381
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• 1998

The large scaled field test by prefabricated vertical drains was performed to evaluate the superiority of vertical discharge capacity for drain materials through compare and analyze the time-settlement behavior with drain spacing and the compression index and consolidation coefficient obtained by laboratory experiments and field monitoring system 1. The relation of measurement settlement( $S_{m}$) versus design settlement( $S_{t}$) and measurement consolidation ratio( $U_{m}$) versus design consolidation ratio( $U_{t}$) were shown $S_{m}$=(1.0~l.1) $S_{t}$, $U_{m}$=(1.13~l.17) $U_{t}$, at 1.0m drain spacing and $S_{m}$=(0.7~0.8) $S_{t}$, $U_{m}$=(0.92~0.99) $U_{t}$ at 1.5m drain spacing, respectively. 2. The relation of field compression index( $C_{cfield}$) and virgin compression index( $V_{cclab}$) was shown $C_{cfield}$=(1.0~1.2) $V_{cclab}$, But it was nearly same value when considered the error with determination method of virgin compression index and prediction method of total settlement. 3. field consolidation coefficient was larger than laboratory consolidation coefficient, and the consolidation coefficient ratio( $C_{h}$/ $C_{v}$) were $C_{h}$=(2.4 ~ 3.0) $C_{v}$. $C_{h}$=(3.5 ~ 4.3) $C_{v}$ at 1.0m and 1.5m drain spacing and increased with increasing of drain spacingngasing of drain spacingng spacingng

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1081-1089
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• 2008

Highly plastic clays in their normally consolidated state are not linear but are concave upwards. Thus their compression index deceases with the increase in consolidation pressure. Likeness the e - log ${\sigma}\;_{\upsilon}\;'$ curves of the silts are not linear but are convex upwards. In this paper, conducted consolidation test with four undisturbed field soil and found that their e - log ${\sigma}\;_{\upsilon}\;'$ plots are not linear. And analyzed difference of settlement between computed value with compression index($C_c$) and computed value with improved compression index($\mathbb{C}$).

• 한국농공학회지
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• 제42권5호
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• pp.133-143
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• 2000

A large scale field test of prefabricated vertical drains was performed to anayze the effect of parameters of the very soft clay at a test site. compression index and the coefficient of horizontal consolidation obtained by back-analysis of settlement data were compared with those obtained by means of laboratory tests. Hyperbolic method, Asaoka meoth and curve fitting method were used to compute final settlement of coefficient of consolidation. The relationships of settlement measurement(Sm) versus design settlement(St) and the measurement consolidation ratio(Um) versus design consolidation (Ut) were shown as Sm=(1.0~1.1) St , Um=(1.13~1.17) Ut at 1.0m spacing of drain and Sm=(0.7~0.8)St, Um= (0.92~0.99) Ut at 1.5 m spacing of drain, respectively . The relationships of the field compression index(CcField) and virgin compression index(vcc lab) were shown as Ccfield =(1.0~1.2)vcc lab . But it was nearly within the same range when considering the error factor with the determination method of virgin compression index and the prediction back-analysis of the settlement data was larger than the coefficient of vertical consolidation, and the ratio of consolidation coefficient (Ch/Cv) was Ch =(2.4~2.9) Cv , Ch=(3.4~4.2) Cv at 1.0m and 1.5m spacing of drain, respectively.

• 한국농공학회지
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• 제45권5호
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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.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.446-449
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• 2002

This paper represents a improved data compression algorithm of mixed text file by 2 byte completion Hangout and 1 byte alphabet from. Original LZW algorithm efficiently compress a alphabet text file but inefficiently compress a 2 byte completion Hangout text file. To solve this problem, data compression algorithm using 2 byte prefix field and 2 byte suffix field for compression table have developed. But it have a another problem that is compression ratio of alphabet text file decreased. In this paper, we proposes improved LZW algorithm, that is, compression table in the Extended LZW(ELZW) algorithm uses 2 byte prefix field for pointer of a table and 1 byte suffix field for repeat counter. where, a prefix field uses a pointer(index) of compression table and a suffix field uses a counter of overlapping or recursion text data in compression table. To increase compression ratio, after construction of compression table, table data are properly packed as different bit string in accordance with a alphabet, Hangout, and pointer respectively. Therefore, proposed ELZW algorithm is superior to 1 byte LZW algorithm as 7.0125 percent and superior to 2 byte LZW algorithm as 11.725 percent. This paper represents a improved data Compression algorithm of mixed text file by 2 byte completion Hangout and 1 byte alphabet form. This document is an example of what your camera-ready manuscript to ITC-CSCC 2002 should look like. Authors are asked to conform to the directions reported in this document.

• 한국지반공학회논문집
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• 제19권6호
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• pp.371-378
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• 2003

한반도 서, 남해안 해성점토에 대하여 초기간극비와 자연함수비 및 액성한계의 물리적 특성과 압축지수와의 상관성을 규명하기 위해 비교적 신뢰성이 크다고 볼 수 있는 대형 항만 공사용 최근자료를 분석하였다. 시료교란의 정도를 분석하기 위하여 각 표본별 실내압밀시험을 실시하고 Schmertmann이 제안한 방법으로 보정하여 수정압축지수를 산정하였다. 또한 이들 자료를 토대로 실내압밀시험으로부터 얻어진 압축지수를 경험적 방법에 의하여 보정한 후 현장 처녀압축곡선과의 관계를 분석하고, 단순회귀분석, 다중회귀분석 및 비선형 회귀분석을 실시하여 최적의 회귀모델을 구한 후 해성점토에 적용할 수 있는 토질특성과 시료교란의 영향을 고려한 압축지수와의 상관 관계식을 제안하였다. 분석 결과, 시료교란의 영향을 경험적 방법으로 평가해 본 결과 현장 압축지수는 실험실 압축지수의 1.16배정도 크게 평가되었다. 해성점토의 물리적 특성과 압축지수의 상관성에 대한 최적의 회귀모형은 토질정수의 누승식 또는 지수승식 형태의 비선형회귀식이 가장 적합한 것으로 나타났다. 또한, 설계 및 실무에 보다 쉽게 적용할 수 있도록 하기 위하여 선형관계식을 사용하는 경우에는 압축지수의 상관식을 물성치의 구간에 따라 구분하여 사용하는 것이 바람직하다.

• 한국지반환경공학회 논문집
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• 제16권6호
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• pp.23-30
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• 2015

본 연구는 국내의 대표적인 연약지반인 남해안 광양지역과 양산지역의 피스톤 샘플러와 대형블록시료로 수행된 실내시험 시료를 이용하여 교란도 분석을 시행하고 교란에 따른 실내시험 압축지수 특성을 평가하기 위하여 계측침하량 분석에 의한 역해석 압축지수와 비교 분석하였다. 본 연구대상지역의 피스톤 시료에 의한 실내시험 결과로 시료교란도 분석을 수행한 결과 대부분 시료가 품질이 불량한 것으로 평가되어 실내시험결과로 산정된 압축지수를 이용한 설계 예측침하량이 과소평가되었음을 알 수 있었다. 인근지역에서 수행된 시험자료에 대한 교란도 분석결과 대형블록시료가 피스톤 시료보다 교란도가 작은 것으로 분석되었다. 계측침하량을 이용한 장래침하량 예측기법인 쌍곡선법, Hoshino법, Asaoka법, ${\sqrt{S}}$법으로 예측한 결과 일부 측점의 예측자료를 제외하고는 예측기법별 신뢰도는 동일한 것으로 분석되었다. 피스톤 시료의 압축지수에 대한 교란영향을 보정하기 위하여 Schmertmann의 수정 압축지수와 계측침하량 분석에 의한 역해석 압축지수를 이용하여 피스톤 시료의 압축지수를 추정하는 새로운 보정식을 제시하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.875-883
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• 2003

Slurry clay has much higher water content than liquid limit of clay and even if small loads apply, it suffers a great settlement. Accordingly it is very difficult to perform a general consolidation test about slurry clay because of high water content. In this study consolidation tests have been performed successfully using Rowe Cell Tester about 1 remolding clay and 3 slurry clays with a water content of 100%, 133% and 150%. From the test results compression index characteristics, secondary compression index characteristics and consolidation coefficient characteristics have been investigated about slurry clay and remolding clay. Also two kinds of theory, by Terzaghi theory and by Mikasa theory, has been used to calculate consolidation coefficients. Compared to the calculation results, they had a similar value of consolidation coefficient. However if Mikasa theory is applied in the field design, the period which reach to the required consolidation degree will be much reduced compared to the period by Terzaghi theory because the time coefficient T$\_$v/ by Mikasa theory is far smaller than T$\_$v/ by Terzaghi theory.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.235-242
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• 2004

For this study, a Peliyagoda area located on a route was selected among many sections of a CKE(Colombo to Katunayake Expressway) route in Sri-Lanka. Its subground consists of a very weak and thick peat soil named amorphous or fibrous peat. All of data, obtained in the design process of soft ground treatment were analyzed to evaluate the settlement characteristics resulted from an embankment load and to present reasonable methods for estimation of secondary compression settlement. For these purposes, soil parameters were used obtainedby field and laboratory tests the settlement analyses were conducted base on the field monitoring results within 20 months. In addition, Reasonable methods were studied to estimate primary consolidation and secondary compression settlement.