• Proceedings of the Korean Geotechical Society Conference
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• 2000.09a
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• pp.9-16
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• 2000

Applicability of the cross shaped drain in a soft clay ground is examined using the laboratory discharge capacity test, column consolidation test and 3-D numerical flow analysis. The equivalent diameter of the tested drains is back-calculated from the laboratory experiment and compared with those calculated from the formula suggested in the literature. The effective range of the cross shaped drain about the discharge capacity and coefficient of permeability is analyzed. The results of numerical analysis show that the cross shaped drain which has a cross-sectional area twice of the band shaped drain can reduce the consolidation time by 30% from that for the band shaped drain in a soft clay ground that K is over 1${\times}$10$\^$-7/cm/sec

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1190-1193
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• 2010

본 연구에서는 점토층의 자중압밀을 시행하여 현장강도를 구현하기 위하여 1/70로 축소 모델링하여 원심모형실험을 수행하였으며, 점토구간에 PBD 타설시의 연약지반의 압밀침하거동을 분석하기 위하여서는 1/100로 축소모델링하여 원심모형실험과 전산해석을 실시하였다. 전산해석결과 성토체중심아래의 점토지반의 침하량은 1단계 성토제방하중 하에서 4.8개월 경과 후 최대 침하량은 41.1cm, 2단계 성토하중에서 4.2개월 경과 후의 최대침하량은 78.8, 3단계 성토하중에서 6개월 경과후의 침하량은 93.5cm의 침하가 발생하는 것으로 나타나 수치해석 결과와 원심모형실험결과 값의 유사한 경향을 확인하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.3-38
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• 2007

The depositional characteristics of Busan clay are initially described in this paper. The deposits of the Nakdong River estuary are composed of some different layers, which have been affected by marine transgression and regression. The upper clay layer is thick and soft. The lower clay layer and some depth of the upper clay layer have been leached by artesian pressure existing in an aquifer below. The clay shows unique physical and engineering characteristics due to leaching. Several large-scale reclamation projects have been performed in this delta area. The preloading method using long vertical drains has been applied for soft ground improvement. Experiences obtained from ground improvement are mentioned in connection with the depositional characteristics of the clay layers.

• Journal of the Korean GEO-environmental Society
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• v.7 no.5
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• pp.67-77
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• 2006

Bearing capacity of soil can be improved by several conventional ground improvement techniques like stabilization and compaction. Recently, the necessity on the reseaches for the bearing capacity of footing reinforced by Geotextile is being significantly increased. In this paper, a series of model tests on sandy ground reinforced by a layer of Geotextile were performed under plane strain condition, and the effects of bearing capacity improvement and behaviour of sandy ground were observed through tests for position and horizontal length, material strength of reinforcement.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.33-40
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• 2000

The horizontal drain method is one of the soil improvement methods in reclamation works using dredged soils. In this method, plastic drain boards are installed horizontally in the ground, and a seepage pressure or negative pressure is applied through one end of these drains. In this study, a basic consolidation test using horizontal drains was conducted to investigate the effectiveness of this method. The configuration of soil box which was used in this test is 100cm(B)${\times}$100cm(L)${\times}$85cm(H). The drain board was reduced to 25mm${\times}$5mm. The variations in settlement and volume of drain water during the consolidation process were measured, and the distribution of water content and the transpormation of horizontal drain were investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1159-1164
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• 2006

In this paper an artificial neural network model is developed to estimate the unconfined compression strength of Deep Cement Mixing(DCM) treated soil. A database which consists of a number of unconfined compression test result compiled from 9 clay sites is used to train and test of the artificial neural network model. Developed neural network model requires water content of soil, unit weight of soil, passing percent of #200 sieve, weight of cement, w-c ratio as input variables. It is found that the developed artificial neural network model can predict more precise and reliable unconfined compression strength than the conventional empirical models.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.990-997
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• 2005

In this paper, the measured results obtained from the ground improved by SCP method at quay-wall caisson foundation in Pusan New Port 1-1 phase are analyzed and then compared with the values predicted by a consolidation theory. The measured settlement is generally smaller than the predicted settlement. For consolidation velocity, the measured velocity is later than the predicted value. According to the execution of caisson placing phases, the predicted value shows higher settlement than the measured one with time being.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1094-1101
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• 2005

The stability of embankment on the soft ground has included problems on stabilities of embanked body and soft soil, which related with vertical displacement and lateral movement of the soft ground especially. The judge methods for the potentialities of lateral movement have been used in order to stabilization assessment during and after construction of the embankment. In this study, the judge methods on the improved soft ground suggested, which compared with exist judge methods on lateral movement. It is due to recent trend using embanked structures on the soft ground most of improved.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.181-188
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• 2004

Composite soil methods among granular pile merhods that we could improve soft ground of fine soil particles by, have permeability as one of fundamental principals. The catual state, that voids of sand or gravel, etc. of granular soil as drainage materials are clogged by fine soil particles, is 'clogging'. In this study, it is analysed that using sand or gravel, etc. of granular soil as drainage materials, experiment are made by clogging tester on several condition.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.692-697
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• 2004

This study is on the increasement of strength about soft ground improvement material using waste residual(paper fly ash, coke ash, slag) by fire. Through this study the authors have analyzed the strength improvement of mixed soft silty sand with improvement materials. The strength of mixed soils with high mixture ratio and more curing days increased. But CA-30(cokes 60%) make more low strength improvement than others. Therefore the authors find out that paper fly ash+cokes, paper fly ash+slag or cokes+slag improvement material is more effect in improvement of soft silty sand than cokes+cenlent. And Ettringite reaction is free mixed soils with more than two materials.