• 한국지반공학회논문집
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• 제15권2호
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• pp.129-138
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• 1999

본 연구는 준설매립 점성토 지반의 토질정수를 효과적으로 구할 수 있는 자중 및 침투압밀시첨 기법과 현장 모형 실험장치의 개발을 중심으로 수행되었다. 이러한 모형 실험장치와 시험기법개발은 연약한 매립 지반의 침강-자중-재하압밀 과정에 대한 재현을 가능케하였다. 이러한 실험적 연구는 준설 점성토 지반의 자중압밀특성을 중심으로 이루어졌으며, 이론적인 연구로 매립점토 지반의 압밀해석시 Terzaghi의 1차원 압밀이론의 적용한계 등을 지적하였고, 이러한 문제점을 고려한 Mikasa의 자중 압밀이론을 토대로 유한차분해석을 실시하였다. 실내시험에 의해 군산 매립점토의 토질정수로 비체적-유효응력-투수계수 관계를 구하였으며 현장 모형실험을 통하여 투입단계부터 간극수압-토압-수위관계 및 침하량 등을 측정하였다. 시험에 의해 얻어진 결과는 Terzaghi의 방법과 Mikasa 자중압밀의 차분해석에 의해 비교.분석되었으며, 실측 침하량은 Terzaghi의 이론보다 Mikasa의 자중압밀이론이 비교적 잘 일치하였다.

• 대한토목학회논문집
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• 제14권3호
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• pp.565-572
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• 1994

본 연구에서는 Terzaghi의 1차원 압밀이론 및 이를 수정한 수정 압밀이론과 성토하중에 의한 측방향으로의 하중감소를 고려하여 연약지반상에서의 압밀거동을 1차원 및 2차원 해석을 통하여 비교분석하였다. 분석결과 1차원 압밀이론을 이용한 성토측면 부근에서의 압밀해석에서는 실측치보다 과다추정하고 있었으며 Terzaghi의 1차원 압밀이론보다는 간극비 및 투수계수의 변화를 고려한 수정압밀이론이 보다 실측치에 근접한 방법임을 알 수 있었다. 1차원 압밀이론 및 지중응력 분포이론을 이용한 각 지점별 압밀해석결과와 2차원 압밀이론으로 해석한 결과를 비교해 보았을 때, 특히 성토측면부에서는 2차원 해석결과보다 1차원 해석결과가 더 크게 과다추정하는 결과를 나타내고 있었으나 시간별 침하의 추세는 거의 차이가 없었으며 물성치의 정확한 선정이 가능하다면 1차원 이론에 의한 해석도 간편하고 합리적인 방법임을 알 수 있었다.

• 한국농공학회논문집
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• 제58권6호
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• pp.71-77
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• 2016

This study was to evaluate the feasibility of pre-consolidation pressure distribution characteristic of western and southern coastal region, using correlation of unconfined compressive strength and preceding research equation. Pre-consolidation of western and southern region showed similar trends undrained shear strength and pre-consolidation pressure in proportion to unconfined compressive strength. Predicted results of U.S. NAVY. (1982) equation revealed a small error western 9.7 % and southern 0.4 %. Prediction correlation results of pre-consolidation using unconfined compressive strength revealed an error western 16.8 % and southern 0.7 %. It was reported that less than 20 percent of pre-consolidation pressure prediction result of Casagrande forecasting error. Estimates of pre-consolidation pressure are possible, before the standard consolidation test, because it was reported that less than 20 % of the forecasting errors of Casagrande.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.513-524
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• 2009

Urban land consolidation, which is to reform land parcels to remove fragmentation and produce ideal blocks, is an effective means for urban renewal. Successful urban land consolidation brings out great benefits to the city officials as well as general public, such as improved city image, increased land value, and more effective land use. However, urban land consolidation can be detrimental to environment, especially in the ecological aspects, while the execution of land consolidation has been focused solely on development for the sake of human benefits. To remove negative effects of urban land consolidation to the ecological system, this paper is intended to establish a set of criteria for evaluating ecological impacts of an urban land consolidation plan. Firstly, key ecological indicators are identified using a special group decision-making process called "habitual domain analysis" and then individual weighting of each indicator is recorded by analytical hierarchy process. An urban ecological evaluation model with 4 levels and 23 indicators is thus developed.

• 한국지반공학회논문집
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• 제21권3호
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• pp.141-148
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• 2005

연약지반의 불균질성, 시료의 교란, 토질상수의 입력오차, 압밀이촌의 단점 등으로 예측된 압밀침하량 및 시간은 대부분 실측치와 잘 일치하지 않고 있다. 따라서 압밀기간동안 계측자료를 활용한 침하량 예측기법은 실무에서 매우 유용한 수단이라 할 수 있다. 본 논문에서는 예측기법으로 많이 활용되는 방곡선법, 아사오카범, 호시노법을 비롯한 최근에 제안된 4법의 이론적 공통점을 바탕으로 아사오카법을 제외한 나머지 분석기법들에 대하여 일반화된 쌍곡선 형태의 수식화 작업으로 새로운 분석 기법을 제안하였으며, 사례를 통하여 유용한 계측분석기법으로 적용성을 확인하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1328-1339
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• 2008

For a commonly used piezocone with a shoulder filter element, dilatory dissipation behavior, which shows an initial temporary increase in pore pressure, has been observed in overconsolidated cohesive soils. However, there is no appropriate way to estimate a consolidation parameter from a dilatory dissipation curve because currently available interpretation methods were developed based on the monotonic decrease of the excess pore pressure. In this study, the interpretation method for evaluation of coefficient of consolidation from a dilatory dissipation result of piezocone test was developed by performing the finite difference analysis on the dissipation after cone penetration. The distribution of the initial excess pore pressure induced by cone penetration, which is the core of the analysis, was estimated from the empirical modification of a solution proposed by cavity expansion theory and critical state concept. And the proposed interpretation method was applied to the field piezocone data and the results were compared to those obtained from laboratory tests. Its reliability was confirmed by the insignificant difference between the values of coefficient of consolidation from piezocone tests and laboratory consolidation tests.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.67-74
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• 1999

Self-Boring Pressuremeter Test(SBPT) is known to be the most effective in-situ test method which can reliably determine consolidation characteristics as well as deformation modules and untrained shear strength. In order to derive the coefficient of consolidation using SBPT results it is necessary to obtain the dissipation behavior from the pore pressure change with time during constant radial strain(generally 10%) and to derive the reliable time factor(Τ) from the analytical method which considers the real in-situ conditions. As previous studies on time factor are based on the assumptions of plane strain condition that the membrane of SBP is infinite, of untrained condition during the expansion of the probe and of elastic soil behavior during consolidation, these analyses can't consider the real boundary conditions and the real soil behaviour. In this study, consolidation analysis similar to real in-situ conditions including test procedure is conducted using finite element program which employs MCC model and Biot theory. Time factor considering the effects of finite membrane length, the total pressure change during consolidation and partial drainage is proposed and compared with previous results.

• 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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• 제38권6호
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• pp.35-41
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• 1996

The theory of consolidation has been achieved remarkable development in terms of theory such as finite consolidation theory, two dimensional Rendulic consolidation theory. Though those theories are well defined, the analysis is by no means straightforward, because associated properties are very difficult to determine in the laboratory, Therefore Terzaghi's one dimensional consolidation theory and Barron's cylindrical consolidation theory are still widely used in engineering practice. The theoretical shortcomings of those consolidation theories and uncertainties of associated properties make inevitably some discrepancy between theoretical and field settlements. Field settlement measurement by settlement plate is, therefore, widely used to overcome the discrepancy. Ultimate settlement is one of the most important factor of embankment construction on soft soils. Nowadays the ultimate settlement prediction methods using field settlement data are widely accepted as a helpful tool for field settlement analysis of embankment construction on soft soils. Among the various methods of ultimate settlement prediction, hyperbolic method and Asaoka's method are most commonly used because of their simplicity and ability to give a reasonable estimate of consolidation settlement. In this paper, the reliability of hyperbolic method and Asaoka's method has been examined using analytical methods. It is shown that both hyperbolic method and Asaoka's method are significantly affected by the direction of drainage.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1693-1706
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• 2008

It is of importance to determine the zero effective stress void ratio($e_{00}$), which is the void ratio at effective stress equal to zero, and the relationships of void ratio-effective stress and of void ratio-hydraulic conductivity for characterizing non-liner finite strain consolidation behavior for ultra-soft dredged materials. The zero effective stress void ratio means a transitional status from sedimentation to self-weight consolidation of very soft soil deposits, and acts as a starting point for self-weight consolidation in the non-linear finite strain numerical analysis such as PSDDF. In this paper, a new method for determining the zero effective stress void ratio has been introduced with the aid of measuring electrical resistivity of the specimen. A correlation between the zero effective stress void ratio and the initial slurry void ratio has been proposed, which can be used in PSDDF analysis as an input parameter. Combining all of the accessible experimental data, the consolidation characteristics of a dredged soil from the Incheon area has been studied in detail.