김성준 Seong-joon Kim , 박민지 Min-ji Park , 안소라 So-ra Ahn , 박근애 Geun-ae Park

DOI: JKWST Vol.49(No.4) 3-12, 2007

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The purpose of this paper is to analyze the relationship between meteorological factors and agricultural reservoir storage, and predict the reservoir storage by multiple regression equation selected by high correlated meteorological factors. Two agricultural reservoirs (Geumgwang and Gosam) located in the upsteam of Gongdo water level gauging station of Anseong-cheon watershed were selected. Monthly reservoir storage data and meteorological data in Suwon weather station of 21 years (1985-2005) were collected. Three cases of correlation (case 1: yearly mean, case 2: seasonal mean dividing a year into 3 periods, and case 3: lagging the reservoir storage from 1 month to 3 months under the condition of case 2) were examined using 8 meteorological factors (precipitation, mean/maximum/minimum temperature, relative humidity, sunshine hour, wind velocity and evaporation). From the correlation analysis, 4 high correlated meteorological factors were selected, and multiple regression was executed for each case. The determination coefficient (R²) of predicted reservoir storage for case 1 showed 0.45 and 0.49 for Geumgwang and Gosam reservoir respectively. The predicted reservoir storage for case 2 showed the highest R² of 0.46 and 0.56 respectively in the period of April to June. The predicted reservoir storage for 1 month lag of case 3 showed the R² of 0.68 and 0.85 respectively for the period of April to June. The results showed that the status of agricultural reservoir storage could be expressed with couple of meteorological factors. The prediction enhanced when the storage data are divided into periods rather than yearly mean and especially from the beginning time of paddy irrigation (April) to high decrease of reservoir storage (June) before Jangma.

함종화 Ham Jong-hwa , 윤춘경 Yoon Chun-gyoung , 다니엘라욱스 Loucks Daniel P.

DOI: JKWST Vol.49(No.4) 13-22, 2007

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The uncertainty in water quality model predictions is inevitably high due to natural stochasticity, model uncertainty, and parameter uncertainty. An integrated modeling system under uncertainty was described and demonstrated for use in watershed management and receiving-water quality prediction. A watershed model (HSPF), a receiving water quality model (WASP), and a wetland model (NPS-WET) were incorporated into an integrated modeling system (modified-BASINS) and applied to the Hwasung Reservoir watershed. Reservoir water quality was predicted using the calibrated integrated modeling system, and the deterministic integrated modeling output was useful for estimating mean water quality given future watershed conditions and assessing the spatial distribution of pollutant loads. A Monte Carlo simulation was used to investigate the effect of various uncertainties on output prediction. Without pollution control measures in the watershed, the concentrations of total nitrogen (T-N) and total phosphorous (T-P) in the Hwasung Reservoir, considering uncertainty, would be less than about 4.8 and 0.26 mg L-1, respectively, with 95% confidence. The effects of two watershed management practices, a wastewater treatment plant (WWTP) and a constructed wetland (WETLAND), were evaluated. The combined scenario (WWTP + WETLAND) was the most effective at improving reservoir water quality, bringing concentrations of T-N and T-P in the Hwasung Reservoir to less than 3.54 and 0.15 mg L^-1, 26.7 and 42.9% improvements, respectively, with 95% confidence. Overall, the Monte Carlo simulation in the integrated modeling system was practical for estimating uncertainty and reliable in water quality prediction. The approach described here may allow decisions to be made based on probability and level of risk, and its application is recommended.

김상호 Sang-ho Kim , 김한중 Han-joong Kim , 홍성구 Seong-gu Hong , 박창언 Chang-eoun Park , 이남호 Nam-ho Lee

DOI: JKWST Vol.49(No.4) 23-31, 2007

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The objective of the study is to prepare input data for FIA (Flood Inundation Analysis) & FDA (Flood Damage Assessment) through rainfall-runoff simulation by HEC-HMS model. For Hwaong watershed (235.6 km²), HEC-HMS was calibrated using 6 storm events. Geospatial data processors, HEC-GeoHMS is used for HEC-HMS basin input data. The parameters of rainfall loss rate and unit hydrograph are optimized from the observed data. HEC-HMS was applied to simulate rainfall-runoff relation to frequency storm at the Hwaong watershed. The results will be used for mitigating and predicting the flood damage after river routing and inundation propagation analysis through various flood scenarios.

원종필 Won Jong Pil , 이재영 Lee Jae Young , 박찬기 Park Chan Gi , 성상경 Sung Sang Kyung , 김완영 Kim Wan Young

DOI: JKWST Vol.49(No.4) 35-41, 2007

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The most agricultural concrete structures for the irrigation and drainage are exposed to the underwater condition at the irrigation period and they take the influence on very severe cold in the winter. Therefore, it is impossible to use repair materials used to the general concrete structures. The research need the development of the repair material for a performance enhance of the agricultural underwater concrete structures. This research evaluated the mechanical and durability performance of the latex modified repair mortar for underwater concrete structures which peformed the repair in the underwater according to the characteristic of the agricultural concrete structure. The latex modified repair mortar is a material that minimize the effect of the ecosystem, environment and the segregation. In this research, the construction condition of the latex modified repair mortar for agricultural concrete structures was considered and the test specimens made in the underwater condition. Test results was then compared with target performance and commercial repair mortar. Experimental test results indicated that the mechanical and durability performance of latex modified repair mortar for agricultural underwater concrete structure satisfied all target performance. Also, the latex modified repair mortar resulted in better repair performance than the commercial repair mortar.

오경윤 Oh Kyung Yoon , 조진구 Cho Jin Goo , 홍종현 Hong Chong Hyun

DOI: JKWST Vol.49(No.4) 43-49, 2007

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The reinforced concrete slab is one of main structure members in the construction industry sector. However, most of researches regarding to RC slabs have been focused on two-dimensional Mindlin-type plate element on the basis of laminated plate theory since three-dimensional solid element has a lot of difficulties in finite element formulation and costs in CPU time. In reality, the RC slabs are subjected to dynamic loads like a heavy traffic vehicle load, and thus should insure the safety from the static load as well as dynamic load. Once we can estimate the dynamic behaviour of RC slabs exactly, it will be very helpful for design of it. In this study, the 20-node solid element has been used to analyze the dynamic characteristics of RC slabs with clamped edges. The elasto-visco plastic model for material non-linearity and the smeared crack model have been adopted in the finite element formulation. The applicability of the proposed finite element has been tested for dynamic behaviour of RC slabs with respect to characteristics of concrete materials in terms of cracking stress, crushing strain, fracture energy and Poisson's ratio. The effect on dynamic behaviour is dependent on not crushing strain but cracking stress, fracture energy and Poisson's ratio. In addition to this, it is shown the damping phenomenon of RC slabs has been identified from the numerical results by using Rayleigh damping.

김영익 Young-ik Kim , 성찬용 Chan-yong Sung

DOI: JKWST Vol.49(No.4) 51-59, 2007

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Recently, concrete has been made porous and used for sound absorption, water permeation, vegetation and water purification according to void characteristics. Many studies are carried out on the utilization sewage sludge, fly ash and waste concrete to reduce the environmental load. This study was performed to evaluate the void, strength, relationship between void and strength, permeability and chemical resistance properties of porous polymer concrete for pavement with different fillers. An unsaturated polyester resin was used as a binder, crushed stone and natural sand were used as an aggregate and bottom ash, fly ash and blast furnace slag were used as fillers. The mix proportions were determined to satisfy the requirement for the permeability coefficient, 1×10^-2㎝/s for general permeable cement concrete pavement in Korea. The void ratios of porous polymer concrete with fillers were in the range of 18~23%. The compressive strength and flexural load of porous polymer concrete with fillers were in the range of 19~22MPa and 18~24KN, respectively. The permeability coefficients of porous polymer concrete with fillers were in the range of 5.5 ×10^-1~9.7×10^-2cm/s. At the sulfuric acid resistance, the weight reduction ratios of porous polymer concrete immersed during 8-week in 5% H₂SO₄ were in the range of 1.08~3.56%.

김찬기 Kim Chan Kee

DOI: JKWST Vol.49(No.4) 63-70, 2007

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The soil samples used in this study were prepared with the residual granite soils passed through the #4 sieve and obtained from Pocheon in Gyeonggi-Ki do. Specifically, five types of samples were prepared. Sample A which is a natural state soil was classified as SM according to the uses. Samples of B, C, D, and E were prepared by mixing Sample A with bentonite and were classified as SC according to the uses. The plasticity indexes of samples B, C, D, and E were 15, 25, 30, and 40, respectively. The specimens, whose dimensions are 100mm by 127.5mm, were prepared by A method of ASTM D 698 with the Proctor mold. In experiments, the loading with the 1%/min was applied. Four different disk diameters, 13mm, 26mm, 38mm, and 52mm were used in the Improved Unconfined Penetration (IUP) tests. To compare the tensile strengths, the split tensile tests were also conducted on the same specimens used for the IUP tests. To find out the effects of moisture contents, plasticity Index of specimens on the tensile strength, six different water contents were used for making a specimen.

이제명 Lee Je-myung , 정남수 Jung Nam-su , 이정재 Lee Jeong-jae

DOI: JKWST Vol.49(No.4) 73-79, 2007

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In the evaluation of rural amenity, it is hard to estimate the worth of rural amenity as numerical values. To evaluate the worth of an abstract idea, information measure technique(IMT) can be used. In this research, rural amenity priority assessment model(RAPAM) was developed adapting IMT. To apply the developed model for assessment of rural amenity, an encyclopedia was used as information gathering and utilizing system(IGUS). The application result of the developed model which was compared with the result of survey have similar trend. R² is 0.8539, RMSE is 0.382 and the applicability of RAPAM was proved.