• Title/Summary/Keyword: Asaoka Method

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Design of Vertical Drain in Consideration of Smear Effect and Well Resistance (교란효과와 배수저항을 고려한 연직 배수재 설계)

  • 이달원
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.4
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    • pp.115-123
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    • 2000
  • This study compared the degree of consolidation by hyperbolic, curve fitting , Asaoka's and methods using values measured with a theoretical curve in consideration of smear effect and well resistance. The degree of consolidation by the Hyperboilc method was underestimated than the degree of consolidation by Curve fitting. Asaoka's , and Monden's methods. The typical range of the coefficient of horizontal consolidation was Ch=(2-3)Cv in the case considering smear effect and well resistance, and Ch =(0.5-2.1) Cv in the case disregarding smear effect and well resistance. The degree of consolidation obtained by ground settlement monitoring was nearly the same value when the coefficient of smear zone permeability by back analysis was shown to be half that of in-situ and the diameter of the smear zone was shown to be double that of mandrel. By increasing the diameter reduction ratio of the drain, the time of consolidation was delayed. The effect of well resistance showed that the case of a small coefficient of permeability was much more than in the case of a large coefficient of permeability . It was recommended that when designing diameter reduction of a drain, well resistance should be considered.

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A Study on the Applicability of Settlement Prediction Method Based on the Field Measurement in Gimpo Hangang Site (김포한강지구 계측자료를 이용한 침하예측기법의 적용성에 관한 연구)

  • Lee, Jungsang;Jeong, Jaewon;Choi, Seungchul;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
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    • v.13 no.12
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    • pp.35-42
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    • 2012
  • There are many large-scale coastal region landfill and land development by loading to use territory efficiently, this regions are mostly soft clay ground. Constructing structures and road on the soft ground bring about engineering problems like ground shear fracture and a big amount of consolidation by bearing capacity. Improvement of soft soil is required to secure soil strength and settlement control. In improvement of soft soil, predict for the amount of settlement based on field surveyed reports are important element for estimating pre-loading banking height and the final point of consolidation. In this study, there is calculating theoretical settlement by analyzing field surveyed report and ground investigation to improvement of soft soil with pre-loading and vertical drain method. And present settlement prediction method reflect soil characteristics in Gimpo Hangang site by analysing prediction settlement and observational settlement during compaction using hyperbolic, ${\sqrt{s}}$, Asaoka method.

Prediction of Settlement for the Highly Plastic and Silty Soft Ground Contained of the Organic Deposits (유기질층을 포함한 고소성 실트질 연약지반의 침하 예측)

  • Yoo, Nam-Jae;Kim, Kyum;Yoo, Chang-Sun
    • Journal of Industrial Technology
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    • v.31 no.B
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    • pp.91-98
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    • 2011
  • In this thesis, from the results of settlement measurement performed at the site where embankment earthwork was carried out on the ground consisting of highly plastic and silty soft soils interlayered with organic deposits, various methods of predicting the embankment settlement such as Hoshino's method, Asaoka's method, hyperbolic method, ${\sqrt{s}}$ method and Monden's method were used to investigate their applicability and the inverse method of finding the soil parameter related to consolidation was used to predict the consolidation behavior in the future. It was confirmed that reliable prediction of consolidation behavior under various conditions could be done to estimate soil parameter related to consolidation such as the consolidation index and consolidation coefficient by the inverse method of comparing the measured settlement with the predicted value by the settlement prediction methods.

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Evaluation of the Degree of Consolidation using Settlement and Excessive Pore Water Pressure (침하량과 간극수압에 의한 압밀도의 평가(지반공학))

  • 이달원;임성훈;윤제식;김지문
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2000.10a
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    • pp.444-450
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    • 2000
  • This study was performed to analyze the degree of consolidation by the dissipation of excessive pore water pressure and final settlement prediction methods of the very soft clay. Hyperbolic method, Asaoka method and curve fitting method were used to compute the degree of consolidation. The degree of consolidation with excessive pore water pressure were used to compute, which considered the dissipation time with embankment construction. The degree of consolidation that was obtained by the peak excessive pore water pressure was less than in the case of the dissipation excessive pore water pressure. And, the degree of consolidation by the total settlement was nearly the same value that of layer settlement. The degree of consolidation that was obtained by excessive pore water pressure was larger than in the case of the settlement.

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Settlement Data Acquisition and Analysis Technique by Personal Computer (Personal Computer를 이용한 침하 안정 관리기법)

  • 송정락;여유현
    • Proceedings of the Korean Geotechical Society Conference
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    • 1991.10a
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    • pp.332-347
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    • 1991
  • Accurate prediction of future settlement is essential for the settlement control of soft soil by pre-loading method. To predict future settlement in clayey soft soils, several methods like Asaoka method, Hyperbolic Method and Hoshino method are currently being used. These methods predict the future sett1ement by mathmatical treatment of the measured settlement data on the basis of consolidtion theory and empiricism. But the correlation coefficient between the measured and the predicted settlement was relatively low (0.8~0.9). Also, the prediction of future settlemet for the design load is very difficult. In this article, the measured field settlement data was treated as the the field consolidation test. Hence, condolidation coefficient(Cv) and compression index(Cc) was evaluated from the field settlement data. Cv and Cc values from field data was used to calculate the degree of consolidation and settlement at desired time. By this method, the correlation coefficent between the measured and the predicted settlement was significantly increased(0.97~0.99). Also the settlement by the design load after the improvement of soft soil could be predicted reasonably. This method is quite rational and sound but it requires thousands of calculation steps. Today, by the aid of low priced personal computers above mentioned technique could be used much acre economically and effectively than conventional methods. This article presented the mechanisms and capacities of this method and demonstrated the enhanced correlation coefficient when applied to actual field settlement data.

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A Comparative Study on the Prediction of the Final Settlement Using Preexistence Method and ARIMA Method (기존기법과 ARIMA기법을 활용한 최종 침하량 예측에 관한 비교 연구)

  • Kang, Seyeon
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.10
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    • pp.29-38
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    • 2019
  • In stability and settlement management of soft ground, the settlement prediction technology has been continuously developed and used to reduce construction cost and confirm the exact land use time. However, the preexistence prediction methods such as hyperbolic method, Asaoka method and Hoshino method are difficult to predict the settlement accurately at the beginning of consolidation because the accurate settlement prediction is possible only after many measurement periods have passed. It is judged as the reason for estimating the future settlement through the proportionality assumption of the slope which the preexistence prediction method computes from the settlement curve. In this study, ARIMA technique is introduced among time series analysis techniques and compared with preexistence prediction methods. ARIMA method was predictable without any distinction of ground conditions, and the results similar to the existing method are predicted early (final settlement).

A Study on the Evaluation of Reliability for Settlement Predictions by Hyperbolic Method (침하예측을 위한 쌍곡선 식의 신뢰성 평가에 관한 연구)

  • 이승우;김유석
    • Geotechnical Engineering
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    • v.13 no.6
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    • pp.5-12
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    • 1997
  • Predictions of settlements under preloading for the improvement of soft soil is a very important element of construction management. Due to the non uniformity, difficulty of estimating resonable soil properties, predictions of settlements and settlement velocities at the design stage seldom agree with the actual future settlements. To overcome this problem, the prediction methods based on the settlement observation of initial preloading stage such as hyperbolic method and Asaoka method have been employed frequently. However the estimating method for the reliability of these predictions at the time of prediction has not been suggested. In this study, comparisons of predicted settlements by hyperbolic met hed and observed settlements are explored through case studies. And a stratagem of estimating reliability of settlement predictions by hyperbolic method is suggested as the result of investigation on the relationship between the initial observed time and error of settlement prediction by hyperbolic method.

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A Study on the Settlement Prediction of Soft Ground Embankment Using Artificial Neural Network (인공신경망을 이용한 연약지반성토의 침하예측 연구)

  • Kim, Dong-Sik;Chae, Young-Su;Kim, Young-Su;Kim, Hyun-Dong
    • Journal of the Korean Geotechnical Society
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    • v.23 no.7
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    • pp.17-25
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    • 2007
  • Various geotechnical problems due to insufficient bearing capacity or excessive settlement are likely to occur when constructing roads or large complexes on soft ground. Accurate predictions of the magnitude of settlement and the consolidation time provide numerous options of ground improvement methods and, thus, enable to save time and expense of the whole project. Asaoka's method is probably the most frequently used one for settlement prediction and the empirical formulae such as Hyperbolic method and Hoshino's method are also often used. To find an elaborate method of predicting the embankment settlement, two recurrent type neural network models, such as Jordan model and Elman-Jordan model, are adopted. The data sets of settlement measured at several domestic sites are analyzed to obtain the most suitable model structures. It was shown from the comparison between predicted and measured settlements that Jordan model provides better predictions than Elman-Jordan model does and that the predictions using CPT results are more accurate than those using SPT results. It is believed that RNN using cone penetration test results can be a highly efficient tool in predicting settlements if enough field data can be obtained.

Cast study on the Design Application of Final Settlement in Soft Ground (연약지반 최종침하량의 설계 적용성에 관한 사례연구)

  • Kim, Young-Su;Park, See-Boum;Kim, Kyung-Tae;Kim, Chang-Hyun;Kim, Hyun-Gu;Yook, Il-Dong;Kim, Hung-Gon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.948-955
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    • 2005
  • In this case of study, Incheon International Airport 2nd phase site preparation 1st section estimated final settlement to improve soft ground. Final settlement is very important in preloading method. Recently, Hyperbolic method, Hoshino method and Asaoka method are used mostly in prediction of final settlement and this paper, Comparing a result of Final settlement, used to Artificial Neural Network. The structure of Dynamic Artificial Neural Network which predicted Final settlement, has application to Young_Jong Island other site, If new investigation data will be added. Also, It is expected to save measuring_system cost in soft ground.

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Consolidation Behavior of Agricultural Reservoir under Embankment on Soft Ground (연약지반상(軟弱地盤上)에 축조(築造)된 농업용저수지(農業用貯水池) 제체의 압밀거동(壓密擧動))

  • Oh, Beom-Hwan;Lee, Dal-Won;Eam, Sung-Hoon
    • Korean Journal of Agricultural Science
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    • v.29 no.2
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    • pp.53-66
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    • 2002
  • This study was performed to evaluation the consolidation behavior of agricultural reservoir in the very soft ground. The final settlement prediction methods by Terzaghi, Hyperbolic and Asaoka methods were used to compare with the degree of consolidation estimated by exess pore water pressure. The dissipated excess pore water pressure during embankment construction and peak excess pore water pressure on the completed embankment were suggested for the estimation of the degree of consolidation. It was concluded that the degree of consolidation estimated from dissipated excess pore water pressure was more reliable than that from the peak excess pore water pressure. The stability methods for agricultural reservoir was used to compare and analyze with various condition by limit equilibrium method.

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