• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.113-125
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• 2002

Ground improvement technique of cement stabilization via Deep Soil Mixing with dry cement is gaining popularity, particularly in Japan and other parts of Southeast Asia and in Scandinavia. Cement can be mixed with deep soft clay deposits, typical of marine environments, to improve the bearing capacity and/or reduce the compressibility of the material so that an otherwise poor site can be developed. However, the strength/deformation behaviour and resulting soil structure of the clay-cement mixture is presently not well understood with respect to both dry and wet mix methods. An extensive laboratory test was carried out to determine the mechanical characteristics of kaolin-cement, with some brief examination of the effects of curing environment. Laboratory tests include triaxial tests, unconfined compression tests, isotropic consolidation testis and oedometer tests. Cement contents up to 10 percent were considered and water curing was employed. Samples were cured for 7 to 112 days while submerged in distilled water. Conventional laboratory tests were also performed. In this paper, the laboratory testing program is described and various sample preparation techniques are discussed. Preliminary triaxial compression test results and trends at varying moisture contents, cement contents, confining pressures and curing times will be presented.

• Geomechanics and Engineering
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• v.6 no.3
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• pp.293-320
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• 2014

In this study, in order to evaluate adequacy of considering local site effect, excluding soil-structure interaction (SSI) effects in inelastic dynamic analysis and design of mid-rise moment resisting building frames, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with two soil types with the shear wave velocities less than 600 m/s, representing soil classes $D_e$ and $E_e$ according to the classification of AS1170.4-2007 (Earthquake actions in Australia) having 30 m bedrock depth. Structural sections of the selected frames were designed according to AS3600:2009 (Australian Standard for Concrete Structures) after undertaking inelastic dynamic analysis under the influence of four different earthquake ground motions. Then the above mentioned frames were analysed under three different boundary conditions: (i) fixed base under direct influence of earthquake records; (ii) fixed base considering local site effect modifying the earthquake record only; and (iii) flexible-base (considering full soil-structure interaction). The results of the analyses in terms of base shears and structural drifts for the above mentioned boundary conditions are compared and discussed. It is concluded that the conventional inelastic design procedure by only including the local site effect excluding SSI cannot adequately guarantee the structural safety for mid-rise moment resisting buildings higher than 5 storeys resting on soft soil deposits.

• Earthquakes and Structures
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• v.19 no.1
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• pp.1-16
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• 2020

This study presents an investigation of the dynamic interactions between a surface structure lying on two different soil deposits and a square-shaped buried structure embedded in the soil. To this end, a large number of numerical models are generated by using a well-known Finite Element Method software, i.e., OpenSEES. The interaction phenomenon is assumed to be affected by six different parameters. In the parametric study, these parameters are assumed to have various values in accordance with the engineering practices. A total of 1620 possible combinations of the parameter values are addressed in this study. 30 different numerical models are also generated as the 'free-field cases' to set a reference. The surface structure drift and acceleration amplifications are used as a measure to evaluate the dynamic interactions. The response (i.e., drifts and accelerations) amplifications are calculated as the ratio of the maximum surface structure response in any 'case' to the maximum surface structure response in corresponding free-field case. Variation of the response amplifications with any of the investigated parameters is addressed in this paper. The results obtained from the numerical analyses clearly reveal that the presence of a buried structure in the vicinity of a surface structure can cause both amplification and de-amplification of the surface structure responses, depending on the case parameters.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.469-478
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• 2005

Understanding of an accurate state of consolidation of underconsolidated clay body, like a recently dredged or reclaimed clay deposits, is one of the most difficult tasks. The estimation of the consolidation status of these clay bodies is often made by laboratory tests of numerical analyses. However these methods demonstrated crucial limitations in the accurate prediction. Therefore, the predicted degree of consolidation from various techniques is verified by actual measured field data. The degree of consolidation of clay body in the East Side Hinterland of Gwangyang Port(2nd Phase) is evaluated in this study by using various techniques such as oedometer test, CPTu, numerical analysis and piezometer tests etc. And the results are compared each other to find the most reliable prediction technique. The merit and reliability of each method is discussed in detail. It is revealed from in this study that the estimation of degree of consolidation by an actual pore water pressure measurements is the most reliable technique.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.228-228
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• 2006

Conjugated oligomers, used as models for fluorene-thiophene copolymers, are compared in terms of the microscopic morphology of thin deposits and the optical properties. The AFM images and the solid-state absorption and emission spectra are interpreted in line with the structural data, in terms of the assembly of the conjugated molecules. The compound with a terthiophene central unit and fluorene end-groups shows well-defined monolayer-by-monolayer assembly into micrometer-long strip-like structures, with a crystalline herringbone-type organization within the monolayers. Polarized confocal microscopy indicates a strong orientation of the crystalline domains within the stripes. In contrast, the compound with a terfluorene central unit and thiophene end groups forms no textured aggregates. The difference in behavior between the two compounds most probably originates from their different capability of forming densely-packed assemblies of ${\pi-pi}$ interacting molecules. These assemblies are used as active elements in organic field effect transistors designed by using soft lithography technique.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2214-2218
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• 2007

The effects of bath temperature on electrochemical behavior, alloy composition, crystallographic structure, morphology and the magnetic properties of electrodeposited Co-Pt-W(P) films were investigated. Electrochemical studies show that alloy electrodeposition has been shifted to more positive potentials and the critical time for nucleation decreased as electrolyte temperature increased. As the temperature increased from 40 oC to 80 oC, tungsten content in the deposit increased, while phosphorus content decreased. The films deposited at T = 40 oC exhibited soft magnetic properties. However, electrodeposited at T = 70 oC, the films exhibited hard magnetic properties. It is also demonstrated that higher temperature more than 70 oC could weaken hard magnetic properties. XRD results indicated that the deposits obtained at 50 oC-70 oC showed enhancement of [00.1] P.O. (preferred orientation) with the bath temperature, which resulted in the stronger perpendicular magnetic anisotropy.

• Journal of the Korean Geotechnical Society
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• v.18 no.2
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• pp.107-121
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• 2002

In this study, GIS(Geographic Information System), a new approaching method, is proposed to effectively manage long-term settlements in the big reclamation sites. To verify an applicability of the proposed method, the prediction of long-term settlements which may occur in the overall soft deposits of the Incheon International Airport is carried out. During the process of the prediction of long-term settlements, measured settlement data obtained from an early stage of preloading are analyzed in detail. For purposes of the analysis, an estimation of the recompression index is also made based on the Nagaraj's research results. The coefficient of the secondary consolidation is further determined based on the relationship presented by the Mesri & Godlewski, which defines a ratio between the coefficient of the secondary consolidation and the recompression index.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.311-315
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• 2006

Various core shapes of cylindrical drains are used for accelerating primary consolidation for soft clay deposits, but serious harmful disadvantages on drainage capacity may occur on cylindrical drains due to confining Pressure when they are installed in that soil. In this study, two different core shapes of cylindrical drain are used to evaluate the drainage capacity with consideration of clogging effects on their filter jackets for an applied confining pressure. Column tests with radial drainage system were conducted under confining pressure of 50 kPa for 13 days. Two parameters which are discharge and accumulated volume of water drained were measured as the time elapsing. From this experimental study, the results showed that at the Initial stage before the clogging developed enough, the cylindrical drain with angular-type-plastic-core could produce discharge twice higher (maximum) than those with round-type. After 13 days had passed on, cylindrical drain with angular-type-plastic-core could produce discharge only 20% higher than those with round-type one. Eventually, there is a possibility that the efficiency of using angular-type-cylindrical-drain will be similar to the round-type one as the clogging develops more.

• Radiation Oncology Journal
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• v.2 no.1
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• pp.71-79
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• 1984

During a 10 year periods, 42 patients with well-documented Midline Malignant Reticulosis were treated with local irradiation and followed for extended periods of time. 13 cases with systemic manifestation after irradiation illustrate the protean features of this disease. Although it commonly Presents in upper airway tracts such as nasal cavity and/or septum, soft palate and palatine tonsil, the lesion may be localized as well as diffuse. 2 cases among them showed systemic relapse on lung, pancreas and scrotum probably from either a multifocal or metastatic deposits. Another 3 eases were associated with systemic diseases such as stomach carcinoma, typhoid enteritis and CNI of fat tissue. Remained cases were diagnosed by clinical or radiological examination. Possibility of close relation to lymphoma with Midline Malignant Reticulosis are also suggested in 1 case. In Midline Malignant Reticulosis, the best results of treatment are obtained in localized lesion of the upper airway treated early with irradiation: A poorer outcome is associated with multifocal systemic involvement, which necessitates a systemic therapy.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.53-61
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• 2017

Seabed settlement and erosion sometimes occurr when a artificial reef is installed in soft seabed. Therefore, this study carried out CBR test and water tank settlement test to investigate settlement behavior of artificial reef according to reinforcement characteristics such as reinforced types and reinforced area. Soil types of ground are sand, silt and clay deposits. Three reinforced types were prepared: unreinforced, geogrid and hybrid bamboo mat(HBM) with different reinforced area. Laboratory test results indicated that reinforced artificial reef improved bearing capacity of ground and reduced settlement as reinforced area increased. Especially, reinforced HBM provided more bearing capacity and less settlement than reinforced geogrid.