• Journal of the Korean Geotechnical Society
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• v.28 no.6
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• pp.39-52
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• 2012

Magnetic sensing system and automated monitoring system based on digital hall sensor for ground settlement are developed to change traditional method for monitoring surface settlement and underground settlement by manual type and to overcome technical limits of existing automated settlement monitoring system. It's possible to monitor surface settlement and underground settlement with multi-points at the same time in a single hole with NX size. It was possible to verify technical confidence and stability by several case studies of soft ground improvement project.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.373-382
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• 2007

In the vertical drain method, discharge capacity is generally one of the most important factor which affect on the estimation of the drain efficiency. However, adopting the drain considering discharge capacity only is not sufficiently considered method so that systematic criteria for adoption is necessary to choose the most suitable drain. Therefore, this study represents the application method considering behavior of the ground and vertical drain which is coupled together and ground improvement efficiency analyzing various cases of discharge capacity test performed in the recent soft ground improvement projects. According to the analysis, most drains tend to satisfy the required discharge capacity. It presents that deformed shape of the drains and well resistance estimation along the ground settlement, improvement efficiency by water content ratio along the depth and shear strength obtained after ground improvement should be considered altogether with the discharge capacity to select the proper drain. Also, appropriate adoption of drain material considering the ground condition is vital through analyzing the field measured data and comparing the result of the discharge capacity test as various vertical drain materials are being constructed continuously.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.509-514
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• 2006

Considering the risk management, there are many examples and various studies for the corporation risk. However, I have never seen the project risk management that applied a construction site for practical approach. Therefore, I have developed a chart (I-Chart) for the project risk management, and also built a model (I-Chart scenario analysis) that I could use. I applied this model to container yard reclaimed land in harbor construction with approaching of geotechnical engineering.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.717-724
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• 2003

Although sand compaction pile is applied considerably for increase of hearing capacity in domestic, it is getting more necessary to develope the alternative materials because of exhaustion and increase of unit cost of sand. In this study, stress concentration ratio between crushed-stone pile and soft ground was measured and, a displacement ratio 30, 40 and 50%, variation of stress concentration ratio was analyzed. As an increase displacement ratio, the stress concentration effect of crushed-stone compaction pile doesn't increase proportionally and effect of ground improvement in case of ground was good at displacement ratio 30% or 40%. The stress concentration ratio of crushed-stone compaction pile in group piles is 1.5 times that of crushed-stone compaction pile in single pile.

• Geotechnical Engineering
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• v.12 no.2
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• pp.115-132
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• 1996

Several soil improvement methods are applied to stabilize soft ground. But, their improvement effects are known to be reduced in view of strength and durability under poor conditions such as marine clay and the ground with the flow of groundwater. The soil improvement method is generally classified as mixing(high pressure) type and injection type, and in this study, for successflll'applications of gelling methods, first in case that mixing method with cement is applied to marine clay, the causes of strength inferiority of treated soil are analyzed, and the effectiveness of improvement is studied, second in case that injection method with water-glass chemical grouts is applied to the ground with the flow of groundwater, soil improvement effects and durability of grouted soil are studied.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.39-46
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• 2019

Most of the soil used for reclamation is marine clay generated from dredging construction.The soft ground made of dredged clay has high water content and high compressibility, so the bearing capacity of the ground is very weak and it is difficult to enter the ground improvement equipment. Therefore, surface hardening treatment method is used to enter equipment prior to full-scale civil engineering work, and stabilizer is mainly used for cement series. Cement-based stabilizers have the advantage of improving the ground in a short period of time and have excellent economic efficiency, but they are disadvantageous in that they cause environmental problems due to leaching of heavy metals such as hexavalent chromium. In this study, environmental effects evaluation of dredged clay mixed with normal portland cement and environmentally friendly stabilizer was evaluated, and uniaxial compressive strength test and indoor model test were conducted to confirm the bearing capacity characteristics of the solidified layer.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.03a
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• pp.43-58
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• 1994

In this reaserch, the comparison between numerical results and field measurments including settlement, heaving and lateral displacement, in the interchange construction works on soft ground. Sand drain was performed for the improvement of the site and steel pipe piles driven for the pier foundation of interchange. The steel pipe piles were replaced to the equivalent steel sheet pile wall. Biot's equation was coupled with elasto-viscoplastic model for the multi-purpose program of soft foundation. Finally countemeasures for future possible lateral displacement and settlement were exmanined.

• Journal of the Korean Geotechnical Society
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• v.24 no.2
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• pp.15-25
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• 2008

A soft ground improvement method is used for structures which are constructed on soft ground to decrease settlement and Increase bearing capacity. The Floating Base Plate has been developed for such purposes. In this study, the load-settlement characteristics were investigated by numerical analysis on various Floating Base Plate shapes to select an optimum shape, different from the conventional shape. The selected optimum shape was used to perform plate bearing test and numerical simulations. It was found that the Floating Base Plate is very effective In reducing the settlement and increasing the bearing capacity.

• Journal of the Korean Geotechnical Society
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• v.28 no.8
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• pp.89-99
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• 2012

The expansion of a road on soft ground could induce an additional settlement to the existing road because of the consolidation characteristics of the soft soil layer subjected to additional load by an adjacent banking. In such case, the existing road could be faced with various problems during the stages of the construction and maintenance, such as deterioration of not only the surface smoothness yielding the decrease in automobile performance safety but also the structural stability of the embankment. These kinds of problems are expected to occur more freguently especially for the deep ground level with a fairly thick soft soil layer. Therefore, they should be examined and studied adequately during the design stage. As a reference case study, this paper deals with the project named Namhae Expressway of 2nd Branch with the soft soil layer with the thickness upto about 50m. After a lengthy review of the original design, an improved design is proposed.

• Proceedings of the Korean Geotechical Society Conference
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• 1992.10a
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• pp.137-144
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• 1992

This paper reports a case study of dynamic consolidation. The objective of the study is to evaluate the effectiveness of ground improvement at the site for Hyundai Petrochemical Compound constructed at Daesan-Myeon, Seosan-Gun in the western shores of Korea. The site ground was prepared by filling on the existing soft marine deposit which consists of a loose granular soil layer and a medium stiff clay layer. For the stabilization of site ground, the compaction was executed in three different procedures with same pounder weigh, drop height and imprint spacing. The post investigation showed that the object was successfully achieved indicating a significant increase of bearing capacity of the treated ground. In this study the effectiveness of dynamic consolidation is evluated for various factors the applied energy, temping sequences, the radial distance from the imprint location and the depth of bed rock.