• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6C
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• pp.367-377
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• 2008

As part of study to develop LRFD (Load and Resistance Factor Design) codes for foundation structures in Korea, resistance factors for static bearing capacity of driven steel pipe piles were calibrated in the framework of reliability theory. The 57 data sets of static load tests and soil property tests conducted in the whole domestic area were collected and these load test piles were sorted into two cases: SPT N at pile tip less than 50, SPT N at pile tip equal to or more than 50. The static bearing capacity formula and the Meyerhof method using N values were applied to calculate the expected design bearing capacities of the piles. The resistance bias factors were evaluated for the two static design methods by comparing the representative measured bearing capacities with the expected design values. Reliability analysis was performed by two types of advanced methods: the First Order Reliability Method (FORM), and the Monte Carlo Simulation (MCS) method using resistance bias factor statistics. The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, in consideration of the reliability level of the current design practice, redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure. Resistance factors of driven steel pipe piles were recommended based on the results derived from the First Order Reliability Method and the Monte Carlo Simulation method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1C
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• pp.19-29
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• 2008

As a part of study to develop LRFD (Load and Resistance Factor Design) codes for foundation structures in Korea, reliability analyses for driven steel pipe piles are performed and the target reliability indices are selected carefully. The 58 data sets of static load tests and soil property tests conducted in the whole domestic area were collected and analyzed to determine the representative bearing capacities of the piles. The static bearing capacity formula and the Meyerhof method using N values are applied to calculate the expected design bearing capacity of the piles. The resistance bias factors were evaluated for the two static design methods by comparing the representative bearing capacities with the design values. Reliability analysis was performed by two types of advanced methods: First Order Reliability Method (FORM), and Monte Carlo Simulation (MCS) method using resistance bias factor statistics. The static bearing capacity formula exhibited relatively small variation, whereas the Meyerhof method showed relatively high inherent conservatism in the resistance bias factors. Reliability indices for safety factors in the range of 3 to 5 were evaluated respectively as 1.50~2.89 and 1.61~2.72 for both of the static bearing capacity formula and the Meyerhof method. The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, based on the reliability level of the current design practice and considering redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure.

• Korean Journal of Heritage: History & Science
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• v.50 no.4
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• pp.122-147
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• 2017

The Jungsandong sites are distributed across quartz and mica schist formations in Precambrian, and weathering layers include large amounts of non-plastic minerals such as mica, quartz, felspar, amphibole, chlorite and so on, which form the ground of the site. Neolithic pottery from Jungsandong exhibits various brown colors, and black core is developed along the inner part for some samples, and sharp comb-pattern and hand pressure marks can be observed. Their non-plastic particles have various composition, size distribution, sorting and roundness, so they are classified into four types by their characteristic mineral compositions. I-type (feldspar pottery) is including feldspar as the pain component or mica and quartz. II-type (mica pottery) is the combination of chloritized mica, talc, tremolite and diopside. III-type (talc pottery) is with a very small amount of quartz and mica. IV-type (asbestos pottery) is containing tremolite and a very small amount of talc. The inner and outer colors of Jungsandong pottery are somewhat heterogeneous. I-type pottery group shows differences in red and yellow degree, depending on the content of feldspar, and is similar to III-type pottery. II-type is similar to IV-type, because its red degree is somewhat high. The soil of the site is higher in red and yellow degree than pottery from it. The magnetic susceptibility has very wide range of 0.088 to 7.360(${\times}10^{-3}$ SI unit), but is differentiated according to minerals, main components in each type. The ranges of bulk density and absorption ratio of pottery seem to be 1.6 to 1.7 and 13.1 to 26.0%, respectively. Each type of pottery shows distinct section difference, as porosity and absorption ratio increase in the order as follows: I-type (organic matter fixed sample) < III-type and IV-type < I-type < II-type (including IV-type of IJP-15). The reason is that differences in physical property occur according to kind and size of non-plastic particles. Although Jungsandong pottery consists of mixtures of various materials, the site pottery has a geological condition on which all mineral composition of Jungsandong pottery can be provided. There, it is thought that raw materials can be supplied from weathered zone of quartz and mica schist, around the site. However, different constituent minerals, size and rock fragments are shown, suggesting the possibility that there can be more raw material pits. Thus, it is estimated that there may be difference in clay and weathering degree.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.165-172
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• 1996

Symbiotic effectiveness and significance of Bradyrhizobium japonicum strains in five serogroups which were consisted of three corresponding serotype strains, respectively, indigenous to Korean soils were evaluated in terms of utility of strain serogroup for symbiotic improvement on soybean plant. The nodulation by rhizobia of each serogroup on four soybean cultivars(Danweonkong, Kwangkyo, Pangsakong, and Eunhakong) was good in order of USDA 123 > YCK 150 > YCK 117 > YCK 141 > USDA 110 serogroup members. Shoot dry weight of soybean was relatively high with USDA 110 serogroup members as well as with YCK 141 serogroup members, whereas the effectiveness of USDA 123 serogroup members was the lowest among the serogroups examined. In particular, Pangsakong among soybeans inoculated with five-serogroup members was positively outstanding on nodulation and shoot dry weight of the plant. Overall, symbiotic parameters of serogroup members associated with soybean plant such as nodule number, nodule mass, $N_2$ase activity, and shoot dry weight showed significantly different responses at level of 1% probability among both rhizobial serogroups and soybean cultivars, respectively. The rate in symbiotic similarity of the members of each serogroup from F-test ($$P{\leq_-}0.05$$) was 100% for nodule No., 90% for $N_2$ase activity. and 80% for soybean shoot dry weight. Taken together, the results indicated that the serological grouping of B. japonicum could be strongly useful for improving the symbiotic effectiveness hetween soybean and Rhizobium.

• Economic and Environmental Geology
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• v.40 no.4
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• pp.347-360
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• 2007

In order to evaluate the degree and extent of heavy metal pollution and the environmental impacts of abandoned Cu mines in Goseong-gun, soils and paddies were collected from the mine area and have been analysed for heavy metal contents. The heavy metal contents were much higher in mountain soils than in paddy soils. Total content of heavy metals decreased in order of Cu>Zn>Pb>As>Cr>Cd in mountain soils whereas Zn>Pb>Cu>Cr>As>Cd in paddy soils. The extractable amount of heavy metals by 0.1/1N HCl decreased in order of Cu>Pb>Zn>As>Cd>Cr in mountain soils whereas Pb>Cu>Zn>As>Cd>Cr in paddy soils. Although the extraction ratios were highly various depending on the sampling site, their average values were in order of Cd(16%)>Pb(10%)>Cu(9%)>As(4.5%)>Zn-Cr(${\le}2.5%$). The soils investigated were enriched in heavy metals relative to the averages of earth crust as In order of $As{\ge}Cd$>Pb>Zn>Cu>Cr. Pollution index calculated from total or extractable heavy metals of soils indicated that the heavy metal pollution was restricted to mountain soils around abandoned Cu mines, especially the Samsan I mine. The metal contents of brown rice showed no significantly contaminated level as follows; As $nd{\sim}0.87mg/kg,\;Cd\;0.02{\sim}0.34mg/kg,\;Cu\;1.01{\sim}6.25mg/kg,\;Mn\;13.4{\sim}43.2mg/kg,\;Pb\;0.09{\sim}2.83mg/kg,\;and\;Zn\;16.5{\sim}79.1mg/kg$. From the extraction and dispersion properties of heavy metal with the soil pH ($4.5{\sim}7.8$), it can be deduced the conclusion that the heavy metal pollution is spreading in the study area mainly by the detrital migration of waste ore and gangue minerals rather than the dissolution and circulation of heavy metal.

• Journal of the Korean Institute of Landscape Architecture
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• v.46 no.3
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• pp.14-26
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• 2018

The Biotope Area Ratio (BAR) is a quantitative pre-planning index for sustainable development and an integrated indicator for the balanced development of buildings and outdoor spaces. However, it has been pointed out that there are problems in operations management: errors in area calculation, insufficiency in the underground soil condition and depth, reduction in biotope area after construction, and functional failure as a pre-planning index. To address these problems, this study proposes implementing LIM. Since the weights of the BAR are mainly decided by the underground soil condition and depth with land cover types, the study focused on the terrain and pavements. The model should conform to BIM guidelines and standards provided by government agencies and professional organizations. Thus, the scope and Level Of Detail (LOD) of the model were defined, and the method to build a model with BIM software was developed. An apartment complex on sloping ground was selected as a case study, a 3D terrain modeled, paving libraries created with property information on the BAR, and a LIM model completed for the site. Then the BAR was calculated and construction documents were created with the BAR table and pavement details. As results of the study, it was found that the application of the criteria on the BAR and calculation became accurate, and the efficiency of design tasks was improved by LIM. It also enabled the performance of evidence-based design on the terrain and underground structures. To adopt LIM, it is necessary to create and distribute LIM library manuals or templates, and build library content that comply with KBIMS standards. The government policy must also have practitioners submit BIM models in the certification system. Since it is expected that the criteria on planting types in the BAR will be expanded, further research is needed to build and utilize the information model for planting materials.

• Journal of the Korean Geotechnical Society
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• v.30 no.6
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• pp.23-39
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• 2014

An artificial rainwater reservoir installed in urban areas for recycling rainwater is an eco-friendly facility for reducing storm water effluence. However, in order to recycle the rainwater directly, the artificial rainwater reservoir requires an auxiliary system that can remove non-point source pollutants included in the initial rainfall of urban area. Therefore, the conventional soil filtration technology is adopted to capture non-point source pollutants in an economical and efficient way in the purification system of artificial rainwater reservoirs. In order to satisfy such a demand, clogging characteristics of the sand filter layers with different grain-size distributions were studied with real non-point source pollutants. For this, a series of lab-scale chamber tests were conducted to make a prediction model for removal of non-point source pollutants, based on the clogging theory. The laboratory chamber experiments were carried out by permeating two types of artificially contaminated water through five different types of sand filter layers with different grain-size distributions. The two artificial contaminated waters were made by fine marine-clay particles and real non-point source pollutants collected from motorcar roads of Seoul, Korea. In the laboratory chamber experiments, the concentrations of the artificial contaminated water were measured in terms of TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) and compared with each other to evaluate the performance of sand filter layers. In addition, the accumulated weight of pollutant particles clogged in the sand filter layers was estimated. This paper suggests a prediction model for removal of non-point source pollutants with theoretical consideration of the physical characteristics such as the grain-size distribution and composition, and change in the hydraulic conductivity and porosity of sand filter layers. The lumped parameter ${\theta}$ related with the clogging property was estimated by comparing the accumulated weight of pollutant particles obtained from the laboratory chamber experiments and calculated from the prediction model based on the clogging theory. It is found that the lumped parameter ${\theta}$ has a significant influence on the amount of the pollutant particles clogged in the pores of sand filter layers. In conclusion, according to the clogging prediction model, a double-sand-filter layer consisting of two separate layers: the upper sand-filter layer with the effective particle size of 1.49 mm and the lower sand-filter layer with the effective particle size of 0.93 mm, is proposed as the optimum system for removing non-point source pollutants in the field-sized artificial rainwater reservoir.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.1
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• pp.55-64
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• 2011

This study was conducted to investigate the effects of green manure crops and cattle slurry application on rice productivity and nutrient movement in paddy land. Cropping systems used in this study were consisted of five designs, such as mono-cropping rice applied with standard fertilizer (MRS), double-cropping whole crop barley following rice applied with cattle slurry (DWBRC), double-cropping whole crop rye following rice applied with cattle slurry (DWRRC), mono-cropping rice applied with following milk vetch (MRMV) and mono-cropping rice applied with following hairy vetch (MRHV). The field experiments were conducted on the clay loam at Backsanmyun, Kimje, Chunlabukdo province in Korea for three years (May 2006 to Apr. 2009). This study was arranged in completely randomized design with three replicates. Culm and panicle length of rice were higher in MRS than other treatments. Ripened grain ratio was higher in MRS than other treatments. Yield of Grain showed high in MRS, DWBRC and DWRRC than MRMV and MRHV. The yield of dry matter (DM) of whole crop barley in DWBRC increased significantly as compared with that of rye in DWRRC. The pH, and contents of T-N, $P_2O_5$ and organic matter (OM) and exchangeable cation (Ca, Na, Mg and K) in soil samples collected at the end of the experiment were remarkably higher than those at the beginning of the experiment. The concentrations of $NO_3$-N, $NH_4$-N and $PO_4$ in discharge water in DWBRC and DWRRC were higher than MRS.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.103-116
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• 2008

In this study, in-situ testing method, Dynamic Cone Penetration Test(DCPT) was presented to establish a new compaction control criteria with using mechanical property like elastic modulus instead of unit weight for field compaction control. Soil chamber tests and in-situ tests were carried out to confirm DCPT tests can predict the designed elastic modulus after field compaction, and correlation analysis among the DCPT, CBR and resilient modulus of sub grade were performed. Also, DCPT test spacing criteria in the construction site was proposed from the literature review. In the result of laboratory tests, Livneh's equation was the best in correlation between PR of DCPT and CBR, George and Pradesh's equation was the best in the predicted resilient modulus. In the resilient modulus using FWD, Gudishala's equation estimates little larger than predicted resilient modulus and Chen's equation estimates little smaller. And KICT's equation estimates the modulus smaller than predicted resilient modulus. But using the results of laboratory resilient modulus tests considering the deviatoric and confining stress from the moving vehicle, the KICT's equation was the best. In the results of In-situ DCPT tests, the variation of PR can occur according to size distribution of penetrate points. So DCPT test spacing was proposed to reduce the difference of PR. Also it was shows that average PR was different according to subgrade materials although the subgrade was satisfied the degree of compaction. Especially large sized materials show smaller PR, and it is also found that field water contents have influence a lot of degree of compaction but a little on the average PR of the DCPT tests.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.267-276
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• 2010

This study was performed to obtain basic data about vegetation structure and site environment of rare and endangered plant, viola websteri in five natural habitats. The dominant species of Hongcheon habitat were Pyrus pyrifolia (tree layer), Morus bombycis (subtree layer), Pyrus pyrifolia (shrub layer) and Isodon inflexus (herb layer). Mt. Yeonin habitat were dominated by Quercus mongolica (tree layer), Morus bombycis (subtree layer), Philadelphus schrenckii (shrub layer) and Viola websteri (herb layer). Mt. Yumyung habitat were dominated by Cornus controversa (tree layer), Morus bombycis (subtree layer), Fraxinus rhynchophylla (shrub layer) and Adenocaulon himalaicum (herb layer). Mt. Daebu habitat were dominated by Acer mono (tree layer), Staphylea bumalda (subtree layer), Staphylea bumalda(shrub layer) and Dryopteris crassirhizoma (herb layer). And the dominant species of Mt. Worak habitat were Larix leptolepis (tree layer), Fraxinus rhynchophylla (subtree layer), Alangium platanifolium var. macrophylum (shrub layer) and Adenocaulon himalaicum (herb layer). It was found out that the average acidity of soil pH was 5.23; 0.30ds/m for electron conductivity; 12.6% for organic matter content; 0.68% for total nitrogen; 21.66 ppm for available phosphorous; and 23.45 cmol(+)/kg for CEC. Interchangeable cation was decreased in order of $Ca^{2+}$ > $Mg^{2+}$ > $K^{2+}$. Viola websteri had positive association with Polygonatum odoratum var. pluriflorum and Geranium thunbergii but negative association with Poa sphondylodes. Species diversity index(H'), maximum Species diversity index (H' max), evenness(J') and dominance (1-J'), of investigated sites ranged 0.6816 (Mt. Worak)~0.9656 (Mt. Daebu), 1.0000 (Mt. Yeonin)~1.3010 (Hongcheon, Gangwon), 0.5330 (Mt. Worak)~0.8947 (Mt. Daebu) and 0.1053 (Mt. Daebu)~0.4670 (Mt. Worak) in woody layer and 1.0414 (Mt. Yumyung)~1.3295 (Mt. Worak), 1.4314 (Mt. Yumyung)~1.6435 (Mt. Daebu), 0.6984 (Hongcheon, Gangwon)~0.8356 (Mt. Worak) and 0.1644 (Mt. Worak)~0.3016 (Hongcheon, Gangwon) in herb layer, respectively.