• 한국재난정보학회 논문집
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• 제3권1호
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• pp.37-53
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• 2007

Various difficult problems occur due to insufficient bearing capacity or excessive settlements when constructing roads or large complexes. Accurate predictions on the final settlement and consolidation time can help in choosing the ground improvement method and thus enables to save time and expense of the whole project. Asaoka's method is probably the most frequently used for settlement prediction which are based on Terzaghi's one dimensional consolidation theory. Empirical formulae such as Hyperbolic method and Hoshino's method are also often used. However, it is known that the settlement predicted by these methods do not match with the actual settlements. Furthermore these methods cannot be used at design stage when there is no measured data. To find an elaborate method in predicting settlement in embankments using various test results and actual settlement data from domestic sites, Back-Propagation Neural Network(BPNN) and Recurrent Neural Network(RNN) were employed and the most suitable model structures were obtained. Predicted settlement values by the developed models were compared with the measured values as well as numerical analysis results. Analysis of the results showed that RNN yielded more compatible predictions with actual data than BPNN and predictions using cone penetration resistance were closer to actual data than predictions using SPT results. Also, it was found that the developed method were very competitive with the numerical analysis considering the number of input data, complexity and effort in modelling. It is believed that RNN using cone penetration test results can make a highly efficient tool in predicting settlements if enough field data can be obtained.

• 한국지반공학회지:지반
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• 제13권6호
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• pp.25-36
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• 1997

피에조콘을 이용하면 연약지반 개량후 임의의 시점에서 지반의 압밀도를 파악할 수가 있다. 이 경우 임의의 심도에서 피에조콘의 관입을 멈추고 간극수압이 일정한 값에 이를 때까지 간극 수압 소산시험을 실시하는데, 연약지반의 투수계수가 작기 때문에 대체적으로 상당히 오랜 시간 동안 소산시험을 하게 된다. 본 논문에서는 침하 분석기법 가운데 일반적으로 널리 알려져 있는 쌍곡선법, 아사오카법, 호시노법을 이용하여 간극수압 소산시험시의 평형간극수압을 각각 추정한 후 장시간에 걸친 실제 시험결과와 비교함으로써 간극수압 소산시험에 소요되는 시간을 단축할 수 있는 방법을 연구하였다. 그 결과, 호시노법을 이용한 추정방법이 가장 적합한 방법임을 알 수 있었으며 이를 이용한 효율적인 간극수압 소산시험 방법을 제시하였다.

• 한국농공학회지
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• 제38권1호
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• pp.116-127
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• 1996

This paper dealt with FEM analysis of foundation improved with pack drain. The theory on pack drain was scrutinized and observed values in the field were compared with numerical results. Work site of Kwangyang container pier was selected as a ease study in which measurement of settlement and pore water pressure was accurately carried out. Biot's consolidation equation was selected as governing One, coupled with modified Camclay model as constitutive one. Christian and Boehmer's numerical technique was adopted. Behavior of foundation with pack drain is not simple but very complicated. Discontinuity resulted from rigidity difference between adjacent materials, smear effect and complicated boundary conditions should be considered in the behavior analysis of foundation behavior. The results of numerical analysis were influenced by smear zone. In relevant to this effect, finite element analysis was carried out using the reduced horizontal coefficient of permeability in the smear zone; The numerical results were compared with observed values in surface settlement. including pore water pressure. However only lateral di5plaoement by numerical ana1Ysis was shown since its measurement was not performed in the field. The predication of settlement to be developed later can be effectively employed for the obtimization of construction. The predication of residual settlement using the data measured in the field was made by Hoshino, Asaoka and hyperbolic method. Among them, the hyperbolic method proved best one. Settlements accorded well between numsrical and observed values while pore pressure showed a slight difference. Lateral displacement showed largest values at constant distance from ground surface. The validation of foundation analysis improved with pack drain by computer program employed in this study selecting modified Cam-clay model was satisfactorily secured.

• 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.