• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.201-217
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• 1999

Bearing capacity of soil can be improved by several conventional ground improvement techniques like stabilization and compaction. In recent time, the use of reinforced soil has become popular due to the availability of durable strong geosynthetic materials. In this papers, through the laboratory model tests on sandy ground reinforced by mats about the strip footing under plane strain condition, the effects of bearing capacity improvement and behaviour of sandy ground were observed. And bearing capacities calculated by proposed method and measured by tests were compared.

• Korean Journal of Microbiology
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• v.23 no.3
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• pp.230-234
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• 1985

A bacterium which can utilize malonate as a sole carbon source was isolated from soil. This strain was identified to be Acinetobacter calcoaceticus by morphological, cultural, phtsiological and biochemical examination. When this microorganism was grown on malonate as a aole carbon source, the enzymes, such as malonyl-CoA synthetase, isocitrate lyase and malate synthase were induced. These results suggest that in this microorganism, malonate is also assimilated through the proposed pathway in Pseudomonas fluorescens: $malonate{\rightarrow}malonyl-CoA{\rightarrow}acetyl-CoA{\rightarrow}glyoxylate\;cycle$.

• Mycobiology
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• v.28 no.4
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• pp.190-192
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• 2000

Antifungal bacteria for biological control of plant diseases or production of novel antibiotics to plant pathogens were isolated in 1997 from various soils of Ansung, Chunan, Koyang, and Paju in Korea. Sixty-four bacterial strains pre-screened from approximately 1,400 strains were tested on V-8 juice agar against eight plant pathogenic fungi using in vitro bioassay technique for inhibition of mycelial growth. Test pathogens were Alternaria mali, Colletotrichum gloeosporioides, C. orbiculare, Fusarium oxysporum f. sp. cucumerinum, F. oxysporum f. sp. lycopersici, Magnaporthe grisea, Phytophthora capsici, and Rhizoctonia solani. A wide range of antifungal activity of bacterial strains was found against the pathogenic fungi, and strain RC-B77 showed the best antifungal activity. Correlation analysis between inhibition of each fungus and mean inhibition of all eight fungi by 64 bacterial strains revealed that C. gloeosporioides would be best appropriate for detecting bacterial strains producing antibiotics with potential as biocontrol agents for plant pathogens.

• Mycobiology
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• v.48 no.1
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• pp.9-19
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• 2020

Two fungal species of ascomycetes were discovered during the screening of soil microflora from the Gangwon Province in Korea: Didymella chlamydospora sp. nov. (YW23-14) and Microdochium salmonicolor sp. nov. (NC14-294). Morphologically, YW23-14 produces smaller chlamydospores (8.0-17.0 × 7.0-15.0 ㎛) than D. glomerata and D. musae. The strain NC14-294 was characterized by smaller conidiogenous cells (4.9-8.8 × 2.0-3.2 ㎛) compared with the closest strains M. fisheri and M. phragmitis. The detailed descriptions, illustrations, and discussions regarding the morphological and phylogenetical analyses of the closely related species are provided to support the novelty of each species. Thus, YW23-14 and NC14-294 are described here as newly discovered species.

• Journal of the Korean Society of Safety
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• v.14 no.2
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• pp.116-121
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• 1999

When plate anchors are embedded in soft clay, they may undergo a deformation under the pressure of sustained load. The critical depth at which the transition from a shallow to a deep anchor takes place depends on the properties of soil. Laboratory model tests were performed for the short-term net ultimate uplift capacity of a circular anchors with respect to various embedment depths and moisture content in saturated kaolinite. The tests have been conducted with the anchor at two different moisture contents. Based on the model test results, empirical relationships between the net load, rate of strain, and time have been developed. In creep tests of kaolinite for load versus ultimate uplift capacity, the displacement of plate anchors rapidly increases during the primary stage but thereafter becomes constant over a period of time.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.371-376
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• 2002

A biosurfactant-producing bacterial strain was selected from diesel-contaminated soil by measuring the oil-film collapsing activity and identified as Pseudomonas aeruginosa D2D2. When glucose and olive oil were used as carbon sources, 11.46 g/1 of biosurfactant was obtained. Based on TLC analysis, the biosurfactant produced from P. aeruginosa D2D2 was identified as a glycolipid, consisting of two types of biosurfactants (Type I and Type II). The purified glycolipid reduced the surface tension of the culture from 72 dyne/cm to 27 dyne/cm. The hydrophilic and hydrophobic moiety of the biosurfactant were rhamnose and ${\beta}$-hydroxydecanoic acid, as determined by FAB-MS and NMR analyses, respectively.

• Geomechanics and Engineering
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• v.13 no.2
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• pp.353-370
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• 2017

This paper presents a case study and numerical investigation to study the hydro-mechanical response of a shallow landslide in unsaturated slopes subjected to rainfall infiltration using a coupled model. The coupled model was interpreted in details by expressing the balance equations for soil mixture and the coupled constitutive equations. The coupled model was verified against experimental data from the shearing-infiltration triaxial tests. A real case of shallow landslide occurred on Mt. Umyeonsan, Seoul, Korea was employed to explore the influence of rainfall infiltration on the slope stability during heavy rainfall. Numerical results showed that the coupled model accurately predicted the poromechanical behavior of a rainfall-induced landslide by simultaneously linking seepage and stress-strain problems. It was also found that the coupled model properly described progress failure of a slope in a highly transient condition. Through the comparisons between the coupled and uncoupled models, the coupled model provided more realistic analysis results under rainfall. Consequently, the coupled model was found to be feasible for the stability and seepage analysis of practical engineering problems.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.6
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• pp.87-92
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• 2007

Strain-stress behavior of soil is of importance in dealing with geo-techniques which relate to bearing capacity, slope stability, earth pressure and many geo-technical problems. So understanding mechanism of the behavior and reinforcing soil to the required state has been an issue for many years. This paper presents the possibility of magnetic force in enhancing shear strength. To analyze the reinforcing effect, triaxial compression tests were performed on two sets of steel-sand mixtures, one of which is influenced by permanent magnet, NdFeB. With magnetic force under 50 kPa confining pressure, maximum shear strengths increased according to steel percentages but under 100 kPa, no significant changes in maximum shear strengths occurred. Therefore the analysis by Mohr's circles indicates that magnetic force converts the shearing characteristics of sand into those of clay.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.7-12
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• 1992

The variable node plate bending element, ie, the element with one or two additional mid-side nodes is used in the analysis of mat foundation to generate the nearly ideal grid model in which more nodes are defined near the column location. The plate bending element used in this study is the one based on Mindlin/Reissner plate theory with substitute shear strain field and the nodal stresses of that element are obtained by the local smoothing technique. The interaction of the soil material with the mat foundation is modeled with Winkler springs connected to the nodal points in the mat model. The vertical stiffness of the soil material are represented in terms of a modulus of subgrade reaction and are computed in the same way as to the computation of consistent nodal force of uniform surface loading. Several mesh schemes were proposed and tested to find the most suitable scheme for mat foundation analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.105-110
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• 2008

The behaviour of an unsaturated soil was analyzed by performing $K_0$ consolidated triaxial tests. Unsaturated triaxial tests were performed with matric suctions for weathered soils and could catch stress paths under consolidation and stress-strain relationships under shear. As a result, both isotropic and $K_0$ conditions had similar shear strength envelopes in the same matric suction. Especially, strength parameters could obtain by stress variables based on critical state theory reasonably which was better than those by Mohr circles at failure.